Function helper

packages/compiler-core/src/codegen.ts:179–181

(key)

    pure: false,
    map: undefined,
    helper(key) {
      return `_${helperNameMap[key]}`
    },
    push(code, newlineIndex = NewlineType.None, node) {
      context.code += code
      if (!__BROWSER__ && context.map) {