feat: more flexible squared property read expression, fixes #643 (#646)

* fix: more flexible squared property read expression, fixes #643

* fix: unecessary error wrapping in browser bundles

* style: update code style and types

* perf: use token.value when evalToken

src/parser/index.ts

@@ -1,5 +1,4 @@
 export * from './tokenizer'
 export * from './parser'
 export * from './parse-stream'
-export * from './parse-string-literal'
 export * from './token-kind'

src/parser/match-operator.spec.ts

@@ -1,28 +0,0 @@
-import { matchOperator } from './match-operator'
-import { defaultOperators } from '..'
-import { createTrie } from '../util/operator-trie'
-
-describe('parser/matchOperator()', function () {
-  const trie = createTrie(defaultOperators)
-  it('should match contains', () => {
-    expect(matchOperator('contains', 0, trie)).toBe(8)
-  })
-  it('should match comparision', () => {
-    expect(matchOperator('>', 0, trie)).toBe(1)
-    expect(matchOperator('>=', 0, trie)).toBe(2)
-    expect(matchOperator('<', 0, trie)).toBe(1)
-    expect(matchOperator('<=', 0, trie)).toBe(2)
-  })
-  it('should match binary logic', () => {
-    expect(matchOperator('and', 0, trie)).toBe(3)
-    expect(matchOperator('or', 0, trie)).toBe(2)
-  })
-  it('should not match if word not terminate', () => {
-    expect(matchOperator('true1', 0, trie)).toBe(-1)
-    expect(matchOperator('containsa', 0, trie)).toBe(-1)
-  })
-  it('should match if word boundary found', () => {
-    expect(matchOperator('>=1', 0, trie)).toBe(2)
-    expect(matchOperator('contains b', 0, trie)).toBe(8)
-  })
-})

src/parser/match-operator.ts

@@ -1,14 +0,0 @@
-import { Trie, TrieNode, IDENTIFIER, TYPES } from '../util'
-
-export function matchOperator (str: string, begin: number, trie: Trie, end = str.length) {
-  let node: TrieNode = trie
-  let i = begin
-  let info
-  while (node[str[i]] && i < end) {
-    node = node[str[i++]]
-    if (node['end']) info = node
-  }
-  if (!info) return -1
-  if (info['needBoundary'] && (TYPES[str.charCodeAt(i)] & IDENTIFIER)) return -1
-  return i
-}

src/parser/parser.ts

@@ -48,7 +48,7 @@ export class Parser {
       }
       return new HTML(token)
     } catch (e) {
-      if (e instanceof LiquidError) throw e
+      if (LiquidError.is(e)) throw e
       throw new ParseError(e as Error, token)
     }
   }

src/parser/tokenizer.spec.ts

@@ -1,5 +1,7 @@
 import { LiquidTagToken, HTMLToken, QuotedToken, OutputToken, TagToken, OperatorToken, RangeToken, PropertyAccessToken, NumberToken, IdentifierToken } from '../tokens'
 import { Tokenizer } from './tokenizer'
+import { defaultOperators } from '../render/operator'
+import { createTrie } from '../util/operator-trie'
 
 describe('Tokenizer', function () {
   it('should read quoted', () => {
@@ -15,12 +17,31 @@ describe('Tokenizer', function () {
     // eslint-disable-next-line deprecation/deprecation
     expect(new Tokenizer('foo bar').readWord()).toHaveProperty('content', 'foo')
   })
-  it('should read number value', () => {
-    const token: NumberToken = new Tokenizer('2.33.2').readValueOrThrow() as any
+  it('should read integer number', () => {
+    const token: NumberToken = new Tokenizer('123').readValueOrThrow() as any
     expect(token).toBeInstanceOf(NumberToken)
-    expect(token.whole.getText()).toBe('2')
-    expect(token.decimal!.getText()).toBe('33')
-    expect(token.getText()).toBe('2.33')
+    expect(token.getText()).toBe('123')
+    expect(token.content).toBe(123)
+  })
+  it('should read negative number', () => {
+    const token: NumberToken = new Tokenizer('-123').readValueOrThrow() as any
+    expect(token).toBeInstanceOf(NumberToken)
+    expect(token.getText()).toBe('-123')
+    expect(token.content).toBe(-123)
+  })
+  it('should read float number', () => {
+    const token: NumberToken = new Tokenizer('1.23').readValueOrThrow() as any
+    expect(token).toBeInstanceOf(NumberToken)
+    expect(token.getText()).toBe('1.23')
+    expect(token.content).toBe(1.23)
+  })
+  it('should treat 1.2.3 as property read', () => {
+    const token: PropertyAccessToken = new Tokenizer('1.2.3').readValueOrThrow() as any
+    expect(token).toBeInstanceOf(PropertyAccessToken)
+    expect(token.props).toHaveLength(3)
+    expect(token.props[0].getText()).toBe('1')
+    expect(token.props[1].getText()).toBe('2')
+    expect(token.props[2].getText()).toBe('3')
   })
   it('should read quoted value', () => {
     const value = new Tokenizer('"foo"a').readValue()
@@ -33,11 +54,7 @@ describe('Tokenizer', function () {
   it('should read quoted property access value', () => {
     const value = new Tokenizer('["a prop"]').readValue()
     expect(value).toBeInstanceOf(PropertyAccessToken)
-    expect((value as PropertyAccessToken).variable.getText()).toBe('"a prop"')
-  })
-  it('should throw for broken quoted property access', () => {
-    const tokenizer = new Tokenizer('[5]')
-    expect(() => tokenizer.readValueOrThrow()).toThrow()
+    expect((value as QuotedToken).getText()).toBe('["a prop"]')
   })
   it('should throw for incomplete quoted property access', () => {
     const tokenizer = new Tokenizer('["a prop"')
@@ -277,10 +294,10 @@ describe('Tokenizer', function () {
 
       const pa: PropertyAccessToken = token!.args[0] as any
       expect(token!.args[0]).toBeInstanceOf(PropertyAccessToken)
-      expect((pa.variable as any).content).toBe('arr')
-      expect(pa.props).toHaveLength(1)
-      expect(pa.props[0]).toBeInstanceOf(NumberToken)
-      expect(pa.props[0].getText()).toBe('0')
+      expect(pa.props).toHaveLength(2)
+      expect((pa.props[0] as any).content).toBe('arr')
+      expect(pa.props[1]).toBeInstanceOf(NumberToken)
+      expect(pa.props[1].getText()).toBe('0')
     })
     it('should read a filter with obj.foo argument', function () {
       const tokenizer = new Tokenizer('| plus: obj.foo')
@@ -290,10 +307,10 @@ describe('Tokenizer', function () {
 
       const pa: PropertyAccessToken = token!.args[0] as any
       expect(token!.args[0]).toBeInstanceOf(PropertyAccessToken)
-      expect((pa.variable as any).content).toBe('obj')
-      expect(pa.props).toHaveLength(1)
-      expect(pa.props[0]).toBeInstanceOf(IdentifierToken)
-      expect(pa.props[0].getText()).toBe('foo')
+      expect(pa.props).toHaveLength(2)
+      expect((pa.props[0] as any).content).toBe('obj')
+      expect(pa.props[1]).toBeInstanceOf(IdentifierToken)
+      expect(pa.props[1].getText()).toBe('foo')
     })
     it('should read a filter with obj["foo"] argument', function () {
       const tokenizer = new Tokenizer('| plus: obj["good luck"]')
@@ -304,8 +321,8 @@ describe('Tokenizer', function () {
       const pa: PropertyAccessToken = token!.args[0] as any
       expect(token!.args[0]).toBeInstanceOf(PropertyAccessToken)
       expect(pa.getText()).toBe('obj["good luck"]')
-      expect((pa.variable as any).content).toBe('obj')
-      expect(pa.props[0].getText()).toBe('"good luck"')
+      expect((pa.props[0] as any).content).toBe('obj')
+      expect(pa.props[1].getText()).toBe('"good luck"')
     })
   })
   describe('#readFilters()', () => {
@@ -341,7 +358,7 @@ describe('Tokenizer', function () {
       expect(tokens[2].args).toHaveLength(1)
       expect(tokens[2].args[0]).toBeInstanceOf(PropertyAccessToken)
       expect((tokens[2].args[0] as any).getText()).toBe('foo[a.b["c d"]]')
-      expect((tokens[2].args[0] as any).props[0].getText()).toBe('a.b["c d"]')
+      expect((tokens[2].args[0] as any).props[1].getText()).toBe('a.b["c d"]')
     })
   })
   describe('#readExpression()', () => {
@@ -358,10 +375,10 @@ describe('Tokenizer', function () {
       expect(exp).toHaveLength(1)
       const pa = exp[0] as PropertyAccessToken
       expect(pa).toBeInstanceOf(PropertyAccessToken)
-      expect((pa.variable as any).content).toEqual('a')
-      expect(pa.props).toHaveLength(2)
+      expect(pa.props).toHaveLength(3)
+      expect((pa.props[0] as any).content).toEqual('a')
 
-      const [p1, p2] = pa.props
+      const [, p1, p2] = pa.props
       expect(p1).toBeInstanceOf(IdentifierToken)
       expect(p1.getText()).toBe('')
       expect(p2).toBeInstanceOf(PropertyAccessToken)
@@ -373,8 +390,8 @@ describe('Tokenizer', function () {
       expect(exp).toHaveLength(1)
       const pa = exp[0] as PropertyAccessToken
       expect(pa).toBeInstanceOf(PropertyAccessToken)
-      expect((pa.variable as any).content).toEqual('a')
-      expect(pa.props).toHaveLength(0)
+      expect(pa.props).toHaveLength(1)
+      expect((pa.props[0] as any).content).toEqual('a')
     })
     it('should read expression `a ==`', () => {
       const exp = [...new Tokenizer('a ==').readExpressionTokens()]
@@ -481,6 +498,30 @@ describe('Tokenizer', function () {
       expect(rhs.getText()).toEqual('"\\""')
     })
   })
+  describe('#matchTrie()', function () {
+    const opTrie = createTrie(defaultOperators)
+    it('should match contains', () => {
+      expect(new Tokenizer('contains').matchTrie(opTrie)).toBe(8)
+    })
+    it('should match comparision', () => {
+      expect(new Tokenizer('>').matchTrie(opTrie)).toBe(1)
+      expect(new Tokenizer('>=').matchTrie(opTrie)).toBe(2)
+      expect(new Tokenizer('<').matchTrie(opTrie)).toBe(1)
+      expect(new Tokenizer('<=').matchTrie(opTrie)).toBe(2)
+    })
+    it('should match binary logic', () => {
+      expect(new Tokenizer('and').matchTrie(opTrie)).toBe(3)
+      expect(new Tokenizer('or').matchTrie(opTrie)).toBe(2)
+    })
+    it('should not match if word not terminate', () => {
+      expect(new Tokenizer('true1').matchTrie(opTrie)).toBe(-1)
+      expect(new Tokenizer('containsa').matchTrie(opTrie)).toBe(-1)
+    })
+    it('should match if word boundary found', () => {
+      expect(new Tokenizer('>=1').matchTrie(opTrie)).toBe(2)
+      expect(new Tokenizer('contains b').matchTrie(opTrie)).toBe(8)
+    })
+  })
   describe('#readLiquidTagTokens', () => {
     it('should read newline terminated tokens', () => {
       const tokenizer = new Tokenizer('echo \'hello\'')

src/parser/tokenizer.ts

@@ -1,16 +1,17 @@
 import { FilteredValueToken, TagToken, HTMLToken, HashToken, QuotedToken, LiquidTagToken, OutputToken, ValueToken, Token, RangeToken, FilterToken, TopLevelToken, PropertyAccessToken, OperatorToken, LiteralToken, IdentifierToken, NumberToken } from '../tokens'
-import { Trie, createTrie, ellipsis, literalValues, TokenizationError, TYPES, QUOTE, BLANK, IDENTIFIER } from '../util'
+import { OperatorHandler } from '../render/operator'
+import { TrieNode, LiteralValue, Trie, createTrie, ellipsis, literalValues, TokenizationError, TYPES, QUOTE, BLANK, IDENTIFIER, NUMBER, SIGN } from '../util'
 import { Operators, Expression } from '../render'
 import { NormalizedFullOptions, defaultOptions } from '../liquid-options'
 import { FilterArg } from './filter-arg'
-import { matchOperator } from './match-operator'
 import { whiteSpaceCtrl } from './whitespace-ctrl'
 
 export class Tokenizer {
   p: number
   N: number
   private rawBeginAt = -1
-  private opTrie: Trie
+  private opTrie: Trie<OperatorHandler>
+  private literalTrie: Trie<LiteralValue>
 
   constructor (
     public input: string,
@@ -21,6 +22,7 @@ export class Tokenizer {
     this.p = range ? range[0] : 0
     this.N = range ? range[1] : input.length
     this.opTrie = createTrie(operators)
+    this.literalTrie = createTrie(literalValues)
   }
 
   readExpression () {
@@ -44,10 +46,22 @@ export class Tokenizer {
   }
   readOperator (): OperatorToken | undefined {
     this.skipBlank()
-    const end = matchOperator(this.input, this.p, this.opTrie)
+    const end = this.matchTrie(this.opTrie)
     if (end === -1) return
     return new OperatorToken(this.input, this.p, (this.p = end), this.file)
   }
+  matchTrie<T> (trie: Trie<T>) {
+    let node: TrieNode<T> = trie
+    let i = this.p
+    let info
+    while (node[this.input[i]] && i < this.N) {
+      node = node[this.input[i++]]
+      if (node['end']) info = node
+    }
+    if (!info) return -1
+    if (info['needBoundary'] && (this.peekType(i - this.p) & IDENTIFIER)) return -1
+    return i
+  }
   readFilteredValue (): FilteredValueToken {
     const begin = this.p
     const initial = this.readExpression()
@@ -272,8 +286,8 @@ export class Tokenizer {
     return this.input.slice(this.p, this.N)
   }
 
-  advance (i = 1) {
-    this.p += i
+  advance (step = 1) {
+    this.p += step
   }
 
   end () {
@@ -289,43 +303,68 @@ export class Tokenizer {
   }
 
   readValue (): ValueToken | undefined {
-    const value = this.readQuoted() || this.readRange()
-    if (value) return value
-
-    if (this.peek() === '[') {
-      this.p++
-      const prop = this.readQuoted()
-      if (!prop) return
-      if (this.peek() !== ']') return
-      this.p++
-      return new PropertyAccessToken(prop, [], this.p)
-    }
-
-    const variable = this.readIdentifier()
-    if (!variable.size()) return
-
-    let isNumber = variable.isNumber(true)
-    const props: (QuotedToken | IdentifierToken)[] = []
+    this.skipBlank()
+    const begin = this.p
+    const variable = this.readLiteral() || this.readQuoted() || this.readRange() || this.readNumber()
+    const props: (ValueToken | IdentifierToken)[] = []
     while (true) {
       if (this.peek() === '[') {
-        isNumber = false
         this.p++
         const prop = this.readValue() || new IdentifierToken(this.input, this.p, this.p, this.file)
-        this.readTo(']')
+        this.assert(this.readTo(']') !== -1, '[ not closed')
         props.push(prop)
-      } else if (this.peek() === '.' && this.peek(1) !== '.') { // skip range syntax
+        continue
+      }
+      if (!variable && !props.length) {
+        const prop = this.readIdentifier()
+        if (prop.size()) {
+          props.push(prop)
+          continue
+        }
+      }
+      if (this.peek() === '.' && this.peek(1) !== '.') { // skip range syntax
         this.p++
         const prop = this.readIdentifier()
         if (!prop.size()) break
-        if (!prop.isNumber()) isNumber = false
         props.push(prop)
+        continue
+      }
+      break
+    }
+    if (!props.length) return variable
+    return new PropertyAccessToken(variable, props, this.input, begin, this.p)
+  }
+
+  readNumber (): NumberToken | undefined {
+    this.skipBlank()
+    let decimalFound = false
+    let digitFound = false
+    let n = 0
+    if (this.peekType() & SIGN) n++
+    while (this.p + n <= this.N) {
+      if (this.peekType(n) & NUMBER) {
+        digitFound = true
+        n++
+      } else if (this.peek(n) === '.' && this.peek(n + 1) !== '.') {
+        if (decimalFound || !digitFound) return
+        decimalFound = true
+        n++
       } else break
     }
-    if (!props.length && literalValues.hasOwnProperty(variable.content)) {
-      return new LiteralToken(this.input, variable.begin, variable.end, this.file)
+    if (digitFound && !(this.peekType(n) & IDENTIFIER)) {
+      const num = new NumberToken(this.input, this.p, this.p + n, this.file)
+      this.advance(n)
+      return num
     }
-    if (isNumber) return new NumberToken(variable, props[0] as IdentifierToken)
-    return new PropertyAccessToken(variable, props, this.p)
+  }
+
+  readLiteral (): LiteralToken | undefined {
+    this.skipBlank()
+    const end = this.matchTrie(this.literalTrie)
+    if (end === -1) return
+    const literal = new LiteralToken(this.input, this.p, end, this.file)
+    this.p = end
+    return literal
   }
 
   readRange (): RangeToken | undefined {
@@ -388,7 +427,7 @@ export class Tokenizer {
   }
 
   peekType (n = 0) {
-    return TYPES[this.input.charCodeAt(this.p + n)]
+    return this.p + n >= this.N ? 0 : TYPES[this.input.charCodeAt(this.p + n)]
   }
 
   peek (n = 0): string {

src/render/expression.spec.ts

@@ -1,7 +1,9 @@
 import { Tokenizer } from '../parser'
 import { Drop } from '../drop'
+import { QuotedToken } from '../tokens'
 import { Context } from '../context'
 import { toPromise, toValueSync } from '../util'
+import { evalQuotedToken } from './expression'
 
 describe('Expression', function () {
   const ctx = new Context({})
@@ -32,7 +34,9 @@ describe('Expression', function () {
       expect(await toPromise(create('"foo"').evaluate(ctx, false))).toBe('foo')
       expect(await toPromise(create('false').evaluate(ctx, false))).toBe(false)
     })
-
+    it('should support evalQuotedToken()', async function () {
+      expect(evalQuotedToken(new QuotedToken('"foo"', 0, 5))).toBe('foo')
+    })
     it('should eval property access', async function () {
       const ctx = new Context({
         foo: { bar: 'BAR' },
@@ -162,6 +166,10 @@ describe('Expression', function () {
       const ctx = new Context({ obj: { foo: 'FOO' }, keys: { "what's this": 'foo' } })
       expect(await toPromise(create('obj[keys["what\'s this"]]').evaluate(ctx, false))).toBe('FOO')
     })
+    it('should allow bracket quoted property access', async function () {
+      const ctx = new Context({ 'foo bar': { coo: 'FOO BAR' } })
+      expect(await toPromise(create('["foo bar"].coo').evaluate(ctx, false))).toBe('FOO BAR')
+    })
     it('should support not', async function () {
       expect(await toPromise(create('not 1 < 2').evaluate(ctx))).toBe(false)
     })
@@ -169,6 +177,24 @@ describe('Expression', function () {
       expect(await toPromise(create('not 1 < 2 or not 1 > 2').evaluate(ctx))).toBe(true)
       expect(await toPromise(create('not 1 < 2 and not 1 > 2').evaluate(ctx))).toBe(false)
     })
+    it('should allow variable as squared sub property key', async function () {
+      const ctx = new Context({ 'foo': { bar: 'BAR' }, 'key': 'bar' })
+      expect(await toPromise(create('foo[key]').evaluate(ctx))).toBe('BAR')
+    })
+    it('should allow propertyAccessToken  as squared sub property key', async function () {
+      const ctx = new Context({ 'foo': { bar: 'BAR', key: 'bar' } })
+      expect(await toPromise(create('foo[foo.key]').evaluate(ctx))).toBe('BAR')
+    })
+    it('should allow nested squared property read', async function () {
+      const ctx = new Context({ 'foo': { bar: 'BAR', key: 'bar' } })
+      expect(await toPromise(create('foo[foo["key"]]').evaluate(ctx))).toBe('BAR')
+    })
+    it('should allow string as property read variable', async function () {
+      expect(await toPromise(create('"foo"[2]').evaluate(ctx))).toBe('o')
+    })
+    it('should allow range as property read variable', async function () {
+      expect(await toPromise(create('(3..5).size').evaluate(ctx))).toBe(3)
+    })
   })
 
   describe('sync', function () {

src/render/expression.ts

@@ -1,6 +1,5 @@
-import { RangeToken, OperatorToken, Token, LiteralToken, NumberToken, PropertyAccessToken, QuotedToken, OperatorType, operatorTypes } from '../tokens'
-import { isQuotedToken, isWordToken, isNumberToken, isLiteralToken, isRangeToken, isPropertyAccessToken, UndefinedVariableError, range, isOperatorToken, literalValues, assert } from '../util'
-import { parseStringLiteral } from '../parser'
+import { QuotedToken, RangeToken, OperatorToken, Token, PropertyAccessToken, OperatorType, operatorTypes } from '../tokens'
+import { isRangeToken, isPropertyAccessToken, UndefinedVariableError, range, isOperatorToken, assert } from '../util'
 import type { Context } from '../context'
 import type { UnaryOperatorHandler } from '../render'
 
@@ -36,38 +35,32 @@ export class Expression {
 }
 
 export function * evalToken (token: Token | undefined, ctx: Context, lenient = false): IterableIterator<unknown> {
+  if (!token) return
+  if ('content' in token) return token.content
   if (isPropertyAccessToken(token)) return yield evalPropertyAccessToken(token, ctx, lenient)
   if (isRangeToken(token)) return yield evalRangeToken(token, ctx)
-  if (isLiteralToken(token)) return evalLiteralToken(token)
-  if (isNumberToken(token)) return evalNumberToken(token)
-  if (isWordToken(token)) return token.getText()
-  if (isQuotedToken(token)) return evalQuotedToken(token)
 }
 
 function * evalPropertyAccessToken (token: PropertyAccessToken, ctx: Context, lenient: boolean): IterableIterator<unknown> {
   const props: string[] = []
+  const variable = yield evalToken(token.variable, ctx, lenient)
   for (const prop of token.props) {
     props.push((yield evalToken(prop, ctx, false)) as unknown as string)
   }
   try {
-    return yield ctx._get([token.propertyName, ...props])
+    if (token.variable) {
+      return yield ctx._getFromScope(variable, props)
+    } else {
+      return yield ctx._get(props)
+    }
   } catch (e) {
     if (lenient && (e as Error).name === 'InternalUndefinedVariableError') return null
     throw (new UndefinedVariableError(e as Error, token))
   }
 }
 
-function evalNumberToken (token: NumberToken) {
-  const str = token.whole.content + '.' + (token.decimal ? token.decimal.content : '')
-  return Number(str)
-}
-
 export function evalQuotedToken (token: QuotedToken) {
-  return parseStringLiteral(token.getText())
-}
-
-function evalLiteralToken (token: LiteralToken) {
-  return literalValues[token.literal]
+  return token.content
 }
 
 function * evalRangeToken (token: RangeToken, ctx: Context) {

src/render/string.spec.ts

@@ -1,4 +1,4 @@
-import { parseStringLiteral } from './parse-string-literal'
+import { parseStringLiteral } from './string'
 
 describe('parseStringLiteral()', function () {
   it('should parse octal escape', () => {

src/template/filter.spec.ts

@@ -1,6 +1,6 @@
 import { Context } from '../context'
 import { toPromise } from '../util'
-import { IdentifierToken, NumberToken, QuotedToken } from '../tokens'
+import { NumberToken, QuotedToken } from '../tokens'
 import { Filter } from './filter'
 
 describe('filter', function () {
@@ -13,7 +13,7 @@ describe('filter', function () {
 
   it('should call filter impl with correct arguments', async function () {
     const spy = jest.fn()
-    const thirty = new NumberToken(new IdentifierToken('30', 0, 2), undefined)
+    const thirty = new NumberToken('30', 0, 2, undefined)
     const filter = new Filter('foo', spy, [thirty], liquid)
     await toPromise(filter.render('foo', ctx))
     expect(spy).toHaveBeenCalledWith('foo', 30)
@@ -23,7 +23,7 @@ describe('filter', function () {
       const val = yield this.context._get([valStr])
       return `${this.liquid.testVersion}: ${val + diff}`
     })
-    const ten = new NumberToken(new IdentifierToken('10', 0, 2), undefined)
+    const ten = new NumberToken('10', 0, 2, undefined)
     const filter = new Filter('add', spy, [ten], liquid)
     const val = await toPromise(filter.render('thirty', ctx))
     expect(val).toEqual('1.0: 40')
@@ -33,12 +33,12 @@ describe('filter', function () {
   })
 
   it('should render filters with argument', async function () {
-    const two = new NumberToken(new IdentifierToken('2', 0, 1), undefined)
+    const two = new NumberToken('2', 0, 1, undefined)
     expect(await toPromise(new Filter('add', (a: number, b: number) => a + b, [two], liquid).render(3, ctx))).toBe(5)
   })
 
   it('should render filters with multiple arguments', async function () {
-    const two = new NumberToken(new IdentifierToken('2', 0, 1), undefined)
+    const two = new NumberToken('2', 0, 1, undefined)
     const c = new QuotedToken('"c"', 0, 3)
     expect(await toPromise(new Filter('add', (a: number, b: number, c: number) => a + b + c, [two, c], liquid).render(3, ctx))).toBe('5c')
   })
@@ -49,7 +49,7 @@ describe('filter', function () {
   })
 
   it('should support key value pairs', async function () {
-    const two = new NumberToken(new IdentifierToken('2', 0, 1), undefined)
+    const two = new NumberToken('2', 0, 1, undefined)
     expect(await toPromise(new Filter('add', (a: number, b: number[]) => b[0] + ':' + (a + b[1]), [['num', two]], liquid).render(3, ctx))).toBe('num:5')
   })
 })

src/tokens/literal-token.ts

@@ -1,7 +1,9 @@
 import { Token } from './token'
 import { TokenKind } from '../parser'
+import { literalValues, LiteralValue } from '../util'
 
 export class LiteralToken extends Token {
+  public content: LiteralValue
   public literal: string
   public constructor (
     public input: string,
@@ -11,5 +13,6 @@ export class LiteralToken extends Token {
   ) {
     super(TokenKind.Literal, input, begin, end, file)
     this.literal = this.getText()
+    this.content = literalValues[this.literal]
   }
 }

src/tokens/number-token.ts

@@ -1,12 +1,15 @@
 import { Token } from './token'
-import { IdentifierToken } from './identifier-token'
 import { TokenKind } from '../parser'
 
 export class NumberToken extends Token {
+  public content: number
   constructor (
-    public whole: IdentifierToken,
-    public decimal?: IdentifierToken
+    public input: string,
+    public begin: number,
+    public end: number,
+    public file?: string
   ) {
-    super(TokenKind.Number, whole.input, whole.begin, decimal ? decimal.end : whole.end, whole.file)
+    super(TokenKind.Number, input, begin, end, file)
+    this.content = Number(this.getText())
   }
 }

src/tokens/property-access-token.spec.ts

@@ -1,14 +0,0 @@
-import { QuotedToken, PropertyAccessToken, IdentifierToken } from '.'
-
-describe('PropertyAccessToken', function () {
-  describe('#propertyName', function () {
-    it('should return correct value for IdentifierToken', function () {
-      const token = new PropertyAccessToken(new IdentifierToken('foo', 0, 3), [], 3)
-      expect(token.propertyName).toBe('foo')
-    })
-    it('should return correct value for QuotedToken', function () {
-      const token = new PropertyAccessToken(new QuotedToken('"foo bar"', 0, 9), [], 9)
-      expect(token.propertyName).toBe('foo bar')
-    })
-  })
-})

src/tokens/property-access-token.ts

@@ -1,18 +1,21 @@
 import { Token } from './token'
+import { LiteralToken } from './literal-token'
+import { ValueToken } from './value-token'
 import { IdentifierToken } from './identifier-token'
+import { NumberToken } from './number-token'
+import { RangeToken } from './range-token'
 import { QuotedToken } from './quoted-token'
-import { TokenKind, parseStringLiteral } from '../parser'
+import { TokenKind } from '../parser'
 
 export class PropertyAccessToken extends Token {
-  public propertyName: string
   constructor (
-    public variable: IdentifierToken | QuotedToken,
-    public props: (IdentifierToken | QuotedToken | PropertyAccessToken)[],
-    end: number
+    public variable: QuotedToken | RangeToken | LiteralToken | NumberToken | undefined,
+    public props: (ValueToken | IdentifierToken)[],
+    input: string,
+    begin: number,
+    end: number,
+    file?: string
   ) {
-    super(TokenKind.PropertyAccess, variable.input, variable.begin, end, variable.file)
-    this.propertyName = this.variable instanceof IdentifierToken
-      ? this.variable.getText()
-      : parseStringLiteral(this.variable.getText())
+    super(TokenKind.PropertyAccess, input, begin, end, file)
   }
 }

src/tokens/quoted-token.ts

@@ -1,7 +1,9 @@
 import { Token } from './token'
 import { TokenKind } from '../parser'
+import { parseStringLiteral } from '../render/string'
 
 export class QuotedToken extends Token {
+  public readonly content: string
   constructor (
     public input: string,
     public begin: number,
@@ -9,5 +11,6 @@ export class QuotedToken extends Token {
     public file?: string
   ) {
     super(TokenKind.Quoted, input, begin, end, file)
+    this.content = parseStringLiteral(this.getText())
   }
 }

src/tokens/value-token.ts

@@ -1,6 +1,7 @@
 import { RangeToken } from './range-token'
 import { LiteralToken } from './literal-token'
+import { NumberToken } from './number-token'
 import { QuotedToken } from './quoted-token'
 import { PropertyAccessToken } from './property-access-token'
 
-export type ValueToken = RangeToken | LiteralToken | QuotedToken | PropertyAccessToken
+export type ValueToken = RangeToken | LiteralToken | QuotedToken | PropertyAccessToken | NumberToken

src/util/error.ts

@@ -2,6 +2,11 @@ import * as _ from './underscore'
 import { Token } from '../tokens/token'
 import { Template } from '../template/template'
 
+/**
+ * targeting ES5, extends Error won't create a proper prototype chain, need a trait to kee track of classes
+ */
+const TRAIT = '__liquidClass__'
+
 export abstract class LiquidError extends Error {
   private token!: Token
   public context = ''
@@ -14,6 +19,7 @@ export abstract class LiquidError extends Error {
     super(typeof err === 'string' ? err : err.message)
     if (typeof err !== 'string') Object.defineProperty(this, 'originalError', { value: err, enumerable: false })
     Object.defineProperty(this, 'token', { value: token, enumerable: false })
+    Object.defineProperty(this, TRAIT, { value: 'LiquidError', enumerable: false })
   }
   protected update () {
     Object.defineProperty(this, 'context', { value: mkContext(this.token), enumerable: false })
@@ -22,6 +28,9 @@ export abstract class LiquidError extends Error {
       '\n' + this.stack
     if (this.originalError) this.stack += '\nFrom ' + this.originalError.stack
   }
+  static is (obj: unknown): obj is LiquidError {
+    return obj?.[TRAIT] === 'LiquidError'
+  }
 }
 
 export class TokenizationError extends LiquidError {

src/util/literal.ts

@@ -9,3 +9,6 @@ export const literalValues = {
   'empty': new EmptyDrop(),
   'blank': new BlankDrop()
 }
+
+export type LiteralKey = keyof typeof literalValues
+export type LiteralValue = typeof literalValues[LiteralKey]

src/util/operator-trie.ts

@@ -1,22 +1,25 @@
-import { Operators, OperatorHandler } from '../render/operator'
 import { IDENTIFIER, TYPES } from '../util/character'
 
-interface TrieLeafNode {
-  handler: OperatorHandler;
+interface TrieInput<T> {
+  [key: string]: T
+}
+
+interface TrieLeafNode<T> {
+  data: T;
   end: true;
   needBoundary?: true;
 }
 
-export interface Trie {
-  [key: string]: Trie | TrieLeafNode;
+export interface Trie<T> {
+  [key: string]: Trie<T> | TrieLeafNode<T>;
 }
 
-export type TrieNode = Trie | TrieLeafNode
+export type TrieNode<T> = Trie<T> | TrieLeafNode<T>
 
-export function createTrie (operators: Operators): Trie {
-  const trie: Trie = {}
-  for (const [name, handler] of Object.entries(operators)) {
-    let node: Trie | TrieLeafNode = trie
+export function createTrie<T = any> (input: TrieInput<T>): Trie<T> {
+  const trie: Trie<T> = {}
+  for (const [name, data] of Object.entries(input)) {
+    let node: Trie<T> | TrieLeafNode<T> = trie
 
     for (let i = 0; i < name.length; i++) {
       const c = name[i]
@@ -29,7 +32,7 @@ export function createTrie (operators: Operators): Trie {
       node = node[c]
     }
 
-    node.handler = handler
+    node.data = data
     node.end = true
   }
   return trie

test/e2e/browser.spec.ts

@@ -7,4 +7,18 @@ describe('browser', function () {
       message: 'output "{{huh" not closed, line:1, col:1'
     })
   })
+  it('should throw tokenization error for invalid filter syntax', async () => {
+    const engine = new LiquidUMD()
+    const message = 'expected filter name, line:1, col:10'
+    const stack = [
+      '>> 1| {{ foo | ^ }}',
+      '               ^',
+      `TokenizationError: ${message}`
+    ].join('\n')
+    await expect(engine.parseAndRender('{{ foo | ^ }}')).rejects.toMatchObject({
+      message,
+      stack: expect.stringContaining(stack),
+      name: 'TokenizationError'
+    })
+  })
 })

test/e2e/issues.spec.ts

@@ -454,4 +454,14 @@ describe('Issues', function () {
     const result = engine.parseAndRenderSync(template, { product })
     expect(result).toEqual('This is a love potion!')
   })
+  it('#643 Error When Accessing Subproperty of Bracketed Reference', () => {
+    const engine = new Liquid()
+    const tpl = '{{ ["Key String with Spaces"].subpropertyKey }}'
+    const ctx = {
+      'Key String with Spaces': {
+        subpropertyKey: 'FOO'
+      }
+    }
+    expect(engine.parseAndRenderSync(tpl, ctx)).toEqual('FOO')
+  })
 })