@bojavou/acorn-import-attributes

Import attributes for acorn.

Parses to the stage3 Import Attributes ESTree extension.

Supports both the with and deprecated assert keywords. Both are parsed to the same tree structure. A property attributesKeyword is added to expose which keyword was present in the source.

Usage

npm install @bojavou/acorn-import-attributes

import * as acorn from 'acorn'
import importAttributes from '@bojavou/acorn-import-attributes'

const Parser = acorn.Parser.extend(
  importAttributes({ with: true, assert: true })
)

const source = `
import config from 'config.json' with { type: 'json' }
`.trim()
const tree = Parser.parse(source, {
  ecmaVersion: 'latest',
  sourceType: 'module'
})

{
  type: 'Program',
  body: [{
    type: 'ImportDeclaration',
    specifiers: [..],
    source: ..,
    attributesKeyword: 'with',
    attributes: [{
      type: 'ImportAttribute',
      key: { type: 'Identifier', name: 'type' },
      value: { type: 'Literal', value: 'json' }
    }]
  }]
}

API

importAttributes([options])

The default export is a factory function which produces a plugin. Pass an options object to configure which keywords to recognize.

Options

| Name | Type | Description | Default | | ---- | ---- | ----------- | ------- | | with | boolean | Recognize with as an import attributes keyword. | true | | assert | boolean | Recognize assert as an import attributes keyword. | false |

ESTree

Extensions to the Import Attributes ESTree structure. attributesKeyword is null when no attributes are present.

ImportDeclaration

extend interface ImportDeclaration {
    attributesKeyword: "with" | "assert" | null;
}

ExportNamedDeclaration

extend interface ExportNamedDeclaration {
    attributesKeyword: "with" | "assert" | null;
}

ExportAllDeclaration

extend interface ExportAllDeclaration {
    attributesKeyword: "with" | "assert" | null;
}