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perf(v-for): use faster array population in renderList

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This commit is contained in:
Evan You 2019-10-16 10:42:25 -04:00
parent 32499b16e7
commit b20b922d99
1 changed files with 6 additions and 4 deletions
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10
packages/runtime-core/src/helpers/renderList.ts
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@ -5,14 +5,16 @@ export function renderList(
source: any, source: any,
renderItem: (value: any, key: string | number, index?: number) => VNodeChild renderItem: (value: any, key: string | number, index?: number) => VNodeChild
): VNodeChild[] { ): VNodeChild[] {
let ret: VNodeChild[] = [] let ret: VNodeChild[]
if (isArray(source) || isString(source)) { if (isArray(source) || isString(source)) {
ret = new Array(source.length)
for (let i = 0, l = source.length; i < l; i++) { for (let i = 0, l = source.length; i < l; i++) {
ret.push(renderItem(source[i], i)) ret[i] = renderItem(source[i], i)
} }
} else if (typeof source === 'number') { } else if (typeof source === 'number') {
ret = new Array(source)
for (let i = 0; i < source; i++) { for (let i = 0; i < source; i++) {
ret.push(renderItem(i + 1, i)) ret[i] = renderItem(i + 1, i)
} }
} else if (isObject(source)) { } else if (isObject(source)) {
if (source[Symbol.iterator as any]) { if (source[Symbol.iterator as any]) {
@ -26,5 +28,5 @@ export function renderList(
} }
} }
} }
return ret return ret!
} }