Introduction to jsonc-parser

The jsonc-parser is a powerful npm module for parsing JSON with comments. It addresses the need for handling JSON files that include comments, which is not supported by the standard JSON parser.

Getting Started

To install the jsonc-parser, use the following command:

npm install jsonc-parser

Using jsonc-parser

Here are some of the useful APIs provided by jsonc-parser:

parse

This function parses a JSONC input string and returns a JavaScript object.

 const { parse } = require('jsonc-parser'); const content = ` {
  // This is a comment
  "name": "John Doe",
  "age": 25
}`; const data = parse(content); console.log(data); // Output: { name: 'John Doe', age: 25 } 

parseTree

This function parses a JSONC input string and returns a JSON tree.

 const { parseTree } = require('jsonc-parser'); const content = ` {
  // This is a comment
  "name": "John Doe",
  "age": 25
}`; const tree = parseTree(content); console.log(tree); // Output: JSON tree structure 

findNodeAtLocation

This function finds a node within a JSON tree at the given location.

 const { parseTree, findNodeAtLocation } = require('jsonc-parser'); const content = ` {
  // This is a comment
  "name": "John Doe",
  "age": 25
}`; const tree = parseTree(content); const nameNode = findNodeAtLocation(tree, ['name']); console.log(nameNode); // Output: Node corresponding to 'name' 

modify

This function modifies a JSONC string with changes and returns the modified string.

 const { modify } = require('jsonc-parser'); const content = ` {
  // This is a comment
  "name": "John Doe",
  "age": 25
}`; const edits = modify(content, ['name'], 'Jane Doe', {formattingOptions: {tabSize: 2, insertSpaces: true}}); const newContent = applyEdits(content, edits); console.log(newContent); // Output: Modified JSONC string 

applyEdits

This function applies the list of edits to the JSONC string and returns the new string.

 const { applyEdits } = require('jsonc-parser'); const edits = [ /* array of text edits */ ]; const newContent = applyEdits(originalContent, edits); console.log(newContent); // Output: JSONC string with applied edits 

App Example Using jsonc-parser

Here is a simple Node.js application that makes use of various jsonc-parser APIs:

 const fs = require('fs'); const { parse, parseTree, findNodeAtLocation, modify, applyEdits } = require('jsonc-parser');
const filePath = './data.jsonc';
fs.readFile(filePath, 'utf8', (err, content) => {
  if (err) {
    console.error(err);
    return;
  }

  // Parsing the JSONC content
  const data = parse(content);
  console.log('Parsed Data:', data);

  // Finding a node
  const tree = parseTree(content);
  const ageNode = findNodeAtLocation(tree, ['age']);
  console.log('Age Node:', ageNode);

  // Modifying the content
  const edits = modify(content, ['name'], 'Jane Doe', { tabSize: 2, insertSpaces: true });
  const newContent = applyEdits(content, edits);
  console.log('Modified Content:', newContent);
  
  // Writing the modified content back to file
  fs.writeFile(filePath, newContent, (err) => {
    if (err) {
      console.error(err);
    } else {
      console.log('File updated successfully');
    }
  });
});