Novadesk Docs

Appearance

json Module ​

Work with JSON values and JSON files from the system module.

javascript
import { json } from "system";

Table of Contents ​

json.parse(text) ​

Parses JSON text into a JS value.

Parameters ​

  • text
    • Type: string
    • Description: JSON source text.

Return Value ​

  • Type: any
  • Description: Parsed object/array/value.

Errors ​

  • Throws if text is invalid JSON.

Example ​

javascript
import { json } from "system";

const obj = json.parse('{ "name": "Novadesk", "v": 1 }');
console.log(obj.name, obj.v);

json.stringify(value[, space]) ​

Converts a JS value to JSON text.

Parameters ​

  • value
    • Type: any
  • space
    • Type: number | string
    • Required: No
    • Description: Pretty-print indentation.

Return Value ​

  • Type: string

Example ​

javascript
import { json } from "system";

const s = json.stringify({ name: "Novadesk", ok: true }, 2);
console.log(s);

json.read(path) ​

Reads a JSON file and parses it.

Parameters ​

  • path
    • Type: string
    • Description: Absolute path or path relative to entry script directory.

Return Value ​

  • Type: object | array | null
  • Description:
    • Returns parsed JSON value on success.
    • Returns {} when file is empty/whitespace.
    • Returns null if file cannot be read.

Errors ​

  • Throws if file exists but contains invalid JSON.

Example ​

javascript
import { json } from "system";

const data = json.read("./data/settings.json");
if (data !== null) {
    console.log("theme:", data.theme);
}

json.write(path, value[, merge]) ​

Writes JSON to file.

Parameters ​

  • path
    • Type: string
    • Description: Absolute path or path relative to entry script directory.
  • value
    • Type: any
    • Description: Value to serialize as JSON.
  • merge
    • Type: boolean
    • Required: No
    • Default: false
    • Description:
      • false: overwrite file with pretty JSON.
      • true: apply JSON merge-patch behavior against existing file.

Return Value ​

  • Type: boolean
  • Description: true on success; otherwise false.

Example (overwrite) ​

javascript
import { json } from "system";

const ok = json.write("./data/settings.json", {
    theme: "dark",
    refreshMs: 500
});
console.log("write:", ok);

Example (merge patch) ​

javascript
import { json } from "system";

// Patch only one field in existing JSON file
const ok = json.write("./data/settings.json", { refreshMs: 1000 }, true);
console.log("merge write:", ok);