fix: some filters on undefined variable throws, #140

src/builtin/filters/array.ts

@@ -1,28 +1,42 @@
-import { last } from '../../util/underscore'
+import { isArray, last } from '../../util/underscore'
 import { isTruthy } from '../../render/syntax'
 
 export default {
   'join': (v: any[], arg: string) => v.join(arg === undefined ? ' ' : arg),
-  'last': <T>(v: T[]): T => last(v),
-  'first': <T>(v: T[]): T => v[0],
-  'map': <T1, T2>(arr: {[key: string]: T1}[], arg: string): T1[] => arr.map(v => v[arg]),
+  'last': (v: any) => isArray(v) ? last(v) : '',
+  'first': (v: any) => isArray(v) ? v[0] : '',
+  'map': map,
   'reverse': (v: any[]) => [...v].reverse(),
   'sort': <T>(v: T[], arg: (lhs: T, rhs: T) => number) => v.sort(arg),
-  'size': (v: string | any[]) => v.length,
-  'concat': <T1, T2>(v: T1[], arg: T2[] | T2): (T1 | T2)[] => Array.prototype.concat.call(v, arg),
-  'slice': <T>(v: T[], begin: number, length: number = 1): T[] => {
-    begin = begin < 0 ? v.length + begin : begin
-    return v.slice(begin, begin + length)
-  },
-  'uniq': function<T> (arr: T[]): T[] {
-    const u = {}
-    return (arr || []).filter(val => {
-      if (u.hasOwnProperty(String(val))) return false
-      u[String(val)] = true
-      return true
-    })
-  },
-  'where': function<T> (arr: T[], property: string, value?: any): T[] {
-    return arr.filter(obj => value === undefined ? isTruthy(obj[property]) : obj[property] === value)
-  }
+  'size': (v: string | any[]) => (v && v.length) || 0,
+  'concat': concat,
+  'slice': slice,
+  'uniq': uniq,
+  'where': where
+}
+
+function map<T1, T2> (arr: {[key: string]: T1}[], arg: string): T1[] {
+  return arr.map(v => v[arg])
+}
+
+function concat<T1, T2> (v: T1[], arg: T2[] | T2): (T1 | T2)[] {
+  return Array.prototype.concat.call(v, arg)
+}
+
+function slice<T> (v: T[], begin: number, length: number = 1): T[] {
+  begin = begin < 0 ? v.length + begin : begin
+  return v.slice(begin, begin + length)
+}
+
+function where<T> (arr: T[], property: string, value?: any): T[] {
+  return arr.filter(obj => value === undefined ? isTruthy(obj[property]) : obj[property] === value)
+}
+
+function uniq<T> (arr: T[]): T[] {
+  const u = {}
+  return (arr || []).filter(val => {
+    if (u.hasOwnProperty(String(val))) return false
+    u[String(val)] = true
+    return true
+  })
 }

src/builtin/filters/string.ts

@@ -1,28 +1,51 @@
+/**
+ * String related filters
+ *
+ * * prefer stringify() to String() since `undefined`, `null` should eval ''
+ */
+import { stringify } from '../../util/underscore'
+
 export default {
-  'append': (v: string, arg: string) => v + arg,
-  'prepend': (v: string, arg: string) => arg + v,
-  'capitalize': (str: string) => String(str).charAt(0).toUpperCase() + str.slice(1),
-  'lstrip': (v: string) => String(v).replace(/^\s+/, ''),
-  'downcase': (v: string) => v.toLowerCase(),
-  'upcase': (str: string) => String(str).toUpperCase(),
-  'remove': (v: string, arg: string) => v.split(arg).join(''),
-  'remove_first': (v: string, l: string) => v.replace(l, ''),
-  'replace': (v: string, pattern: string, replacement: string) =>
-    String(v).split(pattern).join(replacement),
-  'replace_first': (v: string, arg1: string, arg2: string) => String(v).replace(arg1, arg2),
-  'rstrip': (str: string) => String(str).replace(/\s+$/, ''),
-  'split': (v: string, arg: string) => String(v).split(arg),
-  'strip': (v: string) => String(v).trim(),
-  'strip_newlines': (v: string) => String(v).replace(/\n/g, ''),
-  'truncate': (v: string, l: number = 50, o: string = '...') => {
-    v = String(v)
-    if (v.length <= l) return v
-    return v.substr(0, l - o.length) + o
-  },
-  'truncatewords': (v: string, l: number = 15, o: string = '...') => {
-    const arr = v.split(/\s+/)
-    let ret = arr.slice(0, l).join(' ')
-    if (arr.length >= l) ret += o
-    return ret
-  }
+  'append': (v: string, arg: string) => stringify(v) + arg,
+  'prepend': (v: string, arg: string) => arg + stringify(v),
+  'capitalize': capitalize,
+  'lstrip': (v: string) => stringify(v).replace(/^\s+/, ''),
+  'downcase': (v: string) => stringify(v).toLowerCase(),
+  'upcase': (str: string) => stringify(str).toUpperCase(),
+  'remove': (v: string, arg: string) => stringify(v).split(arg).join(''),
+  'remove_first': (v: string, l: string) => stringify(v).replace(l, ''),
+  'replace': replace,
+  'replace_first': replaceFirst,
+  'rstrip': (str: string) => stringify(str).replace(/\s+$/, ''),
+  'split': (v: string, arg: string) => stringify(v).split(arg),
+  'strip': (v: string) => stringify(v).trim(),
+  'strip_newlines': (v: string) => stringify(v).replace(/\n/g, ''),
+  'truncate': truncate,
+  'truncatewords': truncateWords
+}
+
+function capitalize (str: string) {
+  str = stringify(str)
+  return str.charAt(0).toUpperCase() + str.slice(1)
+}
+
+function replace (v: string, pattern: string, replacement: string) {
+  return stringify(v).split(pattern).join(replacement)
+}
+
+function replaceFirst (v: string, arg1: string, arg2: string) {
+  return stringify(v).replace(arg1, arg2)
+}
+
+function truncate (v: string, l: number = 50, o: string = '...') {
+  v = stringify(v)
+  if (v.length <= l) return v
+  return v.substr(0, l - o.length) + o
+}
+
+function truncateWords (v: string, l: number = 15, o: string = '...') {
+  const arr = v.split(/\s+/)
+  let ret = arr.slice(0, l).join(' ')
+  if (arr.length >= l) ret += o
+  return ret
 }

src/util/underscore.ts

@@ -28,9 +28,8 @@ export function promisify (fn: any) {
 }
 
 export function stringify (value: any): string {
-  if (isNil(value)) return ''
-  value = toLiquid(value)
-  return String(value)
+  value = toValue(value)
+  return isNil(value) ? '' : String(value)
 }
 
 export function toValue (value: any): any {
@@ -42,7 +41,7 @@ export function isNumber (value: any): value is number {
 }
 
 export function toLiquid (value: any): any {
-  if (isFunction(value.toLiquid)) return toLiquid(value.toLiquid())
+  if (value && isFunction(value.toLiquid)) return toLiquid(value.toLiquid())
   return value
 }