feat: pop/shift/unshift filters from Jekyll

src/filters/array.ts

@@ -11,7 +11,7 @@ export const reverse = argumentsToValue((v: any[]) => [...toArray(v)].reverse())
 
 export function * sort<T> (this: FilterImpl, arr: T[], property?: string): IterableIterator<unknown> {
   const values: [T, string | number][] = []
-  for (const item of toArray(toValue(arr))) {
+  for (const item of toArray(arr)) {
     values.push([
       item,
       property ? yield this.context._getFromScope(item, stringify(property).split('.'), false) : item
@@ -25,7 +25,6 @@ export function * sort<T> (this: FilterImpl, arr: T[], property?: string): Itera
 }
 
 export function sort_natural<T> (input: T[], property?: string) {
-  input = toValue(input)
   const propertyString = stringify(property)
   const compare = property === undefined
     ? caseInsensitiveCompare
@@ -37,7 +36,7 @@ export const size = (v: string | any[]) => (v && v.length) || 0
 
 export function * map (this: FilterImpl, arr: Scope[], property: string): IterableIterator<unknown> {
   const results = []
-  for (const item of toArray(toValue(arr))) {
+  for (const item of toArray(arr)) {
     results.push(yield this.context._getFromScope(item, stringify(property), false))
   }
   return results
@@ -45,7 +44,7 @@ export function * map (this: FilterImpl, arr: Scope[], property: string): Iterab
 
 export function * sum (this: FilterImpl, arr: Scope[], property?: string): IterableIterator<unknown> {
   let sum = 0
-  for (const item of toArray(toValue(arr))) {
+  for (const item of toArray(arr)) {
     const data = Number(property ? yield this.context._getFromScope(item, stringify(property), false) : item)
     sum += Number.isNaN(data) ? 0 : data
   }
@@ -53,20 +52,35 @@ export function * sum (this: FilterImpl, arr: Scope[], property?: string): Itera
 }
 
 export function compact<T> (this: FilterImpl, arr: T[]) {
-  arr = toValue(arr)
   return toArray(arr).filter(x => !isNil(toValue(x)))
 }
 
 export function concat<T1, T2> (v: T1[], arg: T2[] = []): (T1 | T2)[] {
-  v = toValue(v)
-  arg = toArray(arg).map(v => toValue(v))
-  return toArray(v).concat(arg)
+  return toArray(v).concat(toArray(arg))
 }
 
 export function push<T> (v: T[], arg: T): T[] {
   return concat(v, [arg])
 }
 
+export function unshift<T> (v: T[], arg: T): T[] {
+  const clone = [...toArray(v)]
+  clone.unshift(arg)
+  return clone
+}
+
+export function pop<T> (v: T[]): T[] {
+  const clone = [...toArray(v)]
+  clone.pop()
+  return clone
+}
+
+export function shift<T> (v: T[]): T[] {
+  const clone = [...toArray(v)]
+  clone.shift()
+  return clone
+}
+
 export function slice<T> (v: T[] | string, begin: number, length = 1): T[] | string {
   v = toValue(v)
   if (isNil(v)) return []
@@ -77,7 +91,7 @@ export function slice<T> (v: T[] | string, begin: number, length = 1): T[] | str
 
 export function * where<T extends object> (this: FilterImpl, arr: T[], property: string, expected?: any): IterableIterator<unknown> {
   const values: unknown[] = []
-  arr = toArray(toValue(arr))
+  arr = toArray(arr)
   for (const item of arr) {
     values.push(yield this.context._getFromScope(item, stringify(property).split('.'), false))
   }

src/tags/for.ts

@@ -1,5 +1,5 @@
 import { Hash, ValueToken, Liquid, Tag, evalToken, Emitter, TagToken, TopLevelToken, Context, Template, ParseStream } from '..'
-import { toEnumerable } from '../util/collection'
+import { toEnumerable } from '../util'
 import { ForloopDrop } from '../drop/forloop-drop'
 
 const MODIFIERS = ['offset', 'limit', 'reversed']

src/tags/tablerow.ts

@@ -1,4 +1,4 @@
-import { toEnumerable } from '../util/collection'
+import { toEnumerable } from '../util'
 import { ValueToken, Liquid, Tag, evalToken, Emitter, Hash, TagToken, TopLevelToken, Context, Template, ParseStream } from '..'
 import { TablerowloopDrop } from '../drop/tablerowloop-drop'
 

src/util/collection.ts

@@ -1,16 +0,0 @@
-import { isNil, isString, isObject, isArray, isIterable, toValue } from './underscore'
-
-export function toEnumerable<T = unknown> (val: any): T[] {
-  val = toValue(val)
-  if (isArray(val)) return val
-  if (isString(val) && val.length > 0) return [val] as unknown as T[]
-  if (isIterable(val)) return Array.from(val)
-  if (isObject(val)) return Object.keys(val).map((key) => [key, val[key]]) as unknown as T[]
-  return []
-}
-
-export function toArray (val: any) {
-  if (isNil(val)) return []
-  if (isArray(val)) return val
-  return [ val ]
-}

src/util/index.ts

@@ -6,7 +6,6 @@ export * from './underscore'
 export * from './operator-trie'
 export * from './type-guards'
 export * from './async'
-export * from './collection'
 export * from './strftime'
 export * from './liquid-date'
 export * from './timezone-date'

src/util/underscore.ts

@@ -46,6 +46,22 @@ export function stringify (value: any): string {
   return String(value)
 }
 
+export function toEnumerable<T = unknown> (val: any): T[] {
+  val = toValue(val)
+  if (isArray(val)) return val
+  if (isString(val) && val.length > 0) return [val] as unknown as T[]
+  if (isIterable(val)) return Array.from(val)
+  if (isObject(val)) return Object.keys(val).map((key) => [key, val[key]]) as unknown as T[]
+  return []
+}
+
+export function toArray (val: any) {
+  val = toValue(val)
+  if (isNil(val)) return []
+  if (isArray(val)) return val
+  return [ val ]
+}
+
 export function toValue (value: any): any {
   return (value instanceof Drop && isFunction(value.valueOf)) ? value.valueOf() : value
 }