Speed up Barrel Import Has Fix

• Playground Link

Description

A barrel import is a way to consolidate the exports of multiple modules into a single convenient module that can be imported using a single import statement. For instance, import {a, b, c} from './barrel'.

It has some benefits to import each module directly from its own file without going through the barrel file. Such as reducing bundle size, improving building time or avoiding conflicting names.

YAML

id: speed-up-barrel-import
language: typescript
# find the barrel import statement
rule:
  pattern: import {$$$IDENTS} from './barrel'
# rewrite imported identifiers to direct imports
rewriters:
- id: rewrite-identifer
  rule:
    pattern: $IDENT
    kind: identifier
  fix: import $IDENT from './barrel/$IDENT'
# apply the rewriter to the import statement
transform:
  IMPORTS:
    rewrite:
      rewriters: [rewrite-identifer]
      # $$$IDENTS contains imported identifiers
      source: $$$IDENTS
      # join the rewritten imports by newline
      joinBy: "\n"
fix: $IMPORTS

Example

import {a, b, c} from './barrel'

Diff

import {a, b, c} from './barrel'
import a from './barrel/a'
import b from './barrel/b'
import c from './barrel/c'

Contributed by

Herrington Darkholme