worker-echarts/src/save-json/index.js

worker for echarts

class ValueWrapper {
  constructor (value) {
    this.value = value
  }
}
function* iterateObject (obj) {
  for (const key in obj) {
    if (obj.hasOwnProperty(key)) {
      yield [key, obj[key]]
    }
  }
}
export function stringify (value, excludePattern) {
  const date2json = Date.prototype.toJSON // trap
  Date.prototype.toJSON = function toJSON () {
    return { '\0dt': new ValueWrapper(+this) }
  }
  const json = JSON.stringify(value, (key, val) => {
    if (!val) return val
    if (key.startsWith('\0')) {
      if (val instanceof ValueWrapper) {
        return val.value
      }
      return undefined
    }
    if (excludePattern?.test(key)) {
      return undefined
    }
    if (typeof val === 'number') {
      if (Number.isNaN(val) || !Number.isFinite(val)) {
        return { '\0num': new ValueWrapper(val + '') }
      } else {
        return val
      }
    }
    if (typeof val === 'object') {
      const type = Object.prototype.toString.call(val).slice(8, -1)
      switch (type) {
        case 'Error':
          return {
            '\0err': new ValueWrapper([val.name, val.message, val.stack])
          }
        case 'Int8Array':
        case 'Uint8Array':
        case 'Uint8ClampedArray':
        case 'Int16Array':
        case 'Uint16Array':
        case 'Int32Array':
        case 'Uint32Array':
        case 'Float32Array':
        case 'Float64Array':
        case 'Map':
        case 'Set':
          return { '\0arr': new ValueWrapper([type, Array.from(val)]) }
      }
    }
    if (typeof val === 'function') {
      return { '\0fn': new ValueWrapper(val + '') }
    }
    return val
  })
  Date.prototype.toJSON = date2json
  return json
}
export function parse (json) {
  return JSON.parse(json, (key, obj) => {
    if (obj && typeof obj === 'object' && !Array.isArray(obj)) {
      for (const [type, data] of iterateObject(obj)) {
        if (type.charCodeAt(0) === 0) {
          switch (type.slice(1)) {
            case 'dt':
              return new Date(data)
            case 'fn': {
              let body = data
              const matched = /^function (\w+)\(\) { \[native code\] }$/.exec(
                body
              )
              if (matched) return self[matched[1]]
              // Object member function doesn't start with `function` eg `{ f() {} }`
              // if (!/^function |=>/.test(body)) body = 'function ' + body
              // eslint-disable-next-line @typescript-eslint/no-implied-eval
              return new Function(`"use strict"\nreturn (${body})`)()
            }
            case 'num':
              return +data
            case 'err': {
              const [name, message, stack] = data
              const error = new self[name](message)
              error.stack = stack
              return error
            }
            case 'arr':
              return new self[data[0]](data[1])
          }
        }
        return obj
      }
    }
    return obj
  })
}
export default {
  parse,
  stringify
}