arkts json parsing

ArkTS JSON Parsing and Generation

Module Introduction

This module enables the conversion of JSON text to corresponding ArkTS objects or values, as well as the conversion of objects to JSON strings.

Importing the Module

import { JSON } from '@kit.ArkTS';

JSON Parsing

Using JSON.parse

parse(text: string, reviver?: Transformer, options?: ParseOptions): Object | null

This function parses a JSON string to generate the corresponding ArkTS object or null.

• ** Supported from API version 12 in meta - services.
• System Capability: SystemCapability.Utils.Lang

Parameters:

Parameter Name	Type	Required	Description
text	string	Yes	A valid JSON string.
reviver	Transformer	No	A transformation function that can modify the original values generated by parsing. Default: undefined.
options	ParseOptions	No	Configuration for parsing that can control the generated type. Default: undefined.

Return Value:

Type	Description
Object	null

Error Codes:

Error Code ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are missing; 2. Incorrect parameter types; 3. Parameter verification failed.

Example:

let jsonText = '{"name": "John", "age": 30, "city": "ChongQing"}';
let obj = JSON.parse(jsonText);
console.info("getname --- > " + (obj as object)?.["name"]);
console.info("getage --- > " + (obj as object)?.["age"]);
console.info("getcity --- > " + (obj as object)?.["city"]);

In this example, we use the JSON.parse method to obtain the obj object and then retrieve values using (obj as object)?.["name"].

Example with interface:

interface Person {
  name: string;
  age: number;
  city: string;
}
let jsonText = '{"name": "John", "age": 30, "city": "ChongQing"}';
let person: Person = JSON.parse(jsonText) as Person;
console.info("personinterface getpersonname --- > " + person.name);
console.info("personinterface getpersonage --- > " + person.age);
console.info("personinterface getpersoncity --- > " + person.city);

Example with class:

class Persontest {
  name: string = '';
  age: number = 0;
  city: string = '';
}
let jsonText = '{"name": "John", "age": 30, "city": "ChongQing"}';
let persontest: Persontest = JSON.parse(jsonText.toString()) as Persontest;
console.info("personclass getpersontest --- > " + persontest.name);
console.info("personclass getpersontest --- > " + persontest.age);
console.info("personclass getpersontest --- > " + persontest.city);

Converting Objects or Arrays to JSON - JSON.stringify

This method converts an ArkTS object or array to a JSON string, supporting linear container conversion. Non - linear containers are not supported.

• ** Supported from API version 12 in meta - services.
• System Capability: SystemCapability.Utils.Lang

Parameters:

Parameter Name	Type	Required	Description
value	Object	Yes	The ArkTS object or array to be converted. Linear containers are supported for conversion, while non - linear containers are not.
replacer	Transformer	No	During serialization, each property of the value being serialized is transformed and processed by this function. Default: undefined.
space	string	number	No

Return Value:

Type	Description
string	The converted JSON string.

Example:

interface Person {
  name: string;
  age: number;
  city: string;
}
let testobj = { "name": "John", "age": 30, "city": "ChongQing" } as Person;
let str1 = JSON.stringify(testobj);
console.info("jsonstringify getstr1 --- > " + str1);