vite/src/node/plugins/json.ts

Native-ESM powered web dev build tool

/**
 * https://github.com/rollup/plugins/blob/master/packages/json/src/index.js
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file at
 * https://github.com/rollup/plugins/blob/master/LICENSE
 */

import { dataToEsm } from '@rollup/pluginutils'
import { Plugin } from 'rollup'
import { SPECIAL_QUERY_RE } from '../constants'

export interface JsonOptions {
  /**
   * Generate a named export for every property of the JSON object
   * @default true
   */
  namedExports?: boolean
  /**
   * Generate performant output as JSON.parse("stringified").
   * Enabling this will disable namedExports.
   * @default false
   */
  stringify?: boolean
}

// Custom json filter for vite
const jsonExtRE = /\.json($|\?)(?!commonjs-proxy)/

export function jsonPlugin(
  options: JsonOptions = {},
  isBuild: boolean
): Plugin {
  return {
    name: 'vite:json',

    transform(json, id) {
      if (!jsonExtRE.test(id)) return null
      if (SPECIAL_QUERY_RE.test(id)) return null

      try {
        if (options.stringify) {
          if (isBuild) {
            return {
              // during build, parse then double-stringify to remove all
              // unnecessary whitespaces to reduce bundle size.
              code: `export default JSON.parse(${JSON.stringify(
                JSON.stringify(JSON.parse(json))
              )})`,
              map: { mappings: '' }
            }
          } else {
            return `export default JSON.parse(${JSON.stringify(json)})`
          }
        }

        const parsed = JSON.parse(json)
        return {
          code: dataToEsm(parsed, {
            preferConst: true,
            namedExports: options.namedExports
          }),
          map: { mappings: '' }
        }
      } catch (e) {
        const errorMessageList = /[\d]+/.exec(e.message)
        const position = errorMessageList && parseInt(errorMessageList[0], 10)
        const msg = position
          ? `, invalid JSON syntax found at line ${position}`
          : `.`
        this.error(`Failed to parse JSON file` + msg, e.idx)
      }
    }
  }
}