p5.js saveJSON() Function

Last Updated : 12 Jul, 2025
The saveJSON() function is used to write an object or array of objects as a JSON object to the .json file. The saving of the file will vary depending on the web browser. Syntax: 
saveJSON( json, filename, optimize )
Parameters: This function accept three parameters as mentioned above and described below:
  • json: It is an object or array of objects that will form the contents of the JSON object to be created.
  • filename: It specifies the string that is used as the filename of the saved file.
  • optimize: It is a boolean value which specifies if the JSON object would be removed of line breaks and spaces before it is written. It is an optional parameter.
The examples below illustrate the saveJSON() function in p5.js: Example 1: javascript 
function setup() {
  createCanvas(600, 300);
  textSize(22);
  text("Click on the button below to "
      + "save the JSON Object", 20, 20);

  bookObj = {};
  bookObj.name = "Let US C";
  bookObj.author = "Yashavant Kanetkar";
  bookObj.price = "120";

  // Create a button for saving the JSON Object
  saveBtn = createButton("Save JSON object to file");
  saveBtn.position(30, 50)
  saveBtn.mousePressed(saveFile);
}

function saveFile() {

  // Save the JSON object to file
  saveJSON(bookObj, 'books.json', true);
}
Output: save-json-obj Example 2: javascript 
function setup() {
  createCanvas(600, 300);
  textSize(22);
  text("Click on the button below to "
      + "save the JSON Array", 20, 20);

  bookArray = [];

  for (let i = 1; i <= 3; i++) {
    bookObj = {};
    bookObj.name = "Book " + i;
    bookObj.author = "Author " + i;

    bookArray.push(bookObj);
  }

  // Create a button for saving JSON Object
  saveBtn = createButton("Save JSON Array to file");
  saveBtn.position(30, 50)
  saveBtn.mousePressed(saveFile);
}

function saveFile() {

  // Save the JSON object to file
  saveJSON(bookArray, 'books-list.json');
}
Output: save-json-array Online editor: https://editor.p5js.org/ Environment Setup: https://www.geeksforgeeks.org/javascript/p5-js-soundfile-object-installation-and-methods/ Reference: https://p5js.org/reference/#/p5/saveJSON
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