_Create Download or Load File from Console.md

Overview

Useful for snippets if you want to merge in additional data

Exporting

Calling the downloadData() function will immediately create a file download (as though you right clicked to download the file within the browser) for the data you provide - in JSON format.

Importing

When you run this script:

1. A file dialog opens up requesting a file
2. It reads the file in a plain text
3. It parses the file as JSON
4. you can then do what you want with the JSON

exportJson.js

/* Auxiliary function to download a file with the exported data */
function downloadData(filename, data) {
  const file = new File([data], { type: 'text/json' });
  const elem = document.createElement('a');
  elem.href = URL.createObjectURL(file);
  elem.download = filename;
  elem.click();
}
  
// downloadData('someFile', JSON.stringify(objectToExport));

importJson.js

(async function importFile() {
  /* Auxiliary function to open a file selection dialog */
  function selectFileToRead() {
    return new Promise((resolve) => {
      const input = document.createElement('input');
      input.setAttribute('type', 'file');
      input.addEventListener('change', (e) => {
        resolve(e.target.files[0]);
      }, false);
      input.click();
    });
  }

  /* Auxiliary function to read data from a file */
  function readFile(file) {
    return new Promise((resolve) => {
      const reader = new FileReader();
      reader.addEventListener('load', (e) => {
        resolve(e.target.result);
      });
      reader.readAsText(file);
    });
  }

  const file = await selectFileToRead();
  const content = await readFile(file);
  let jsonContents = JSON.parse(content);
  console.log(`found: jsonContents - and do with it what you will}`);
  // add your code here...
}());