[javascript] How to read a local text file?

If you want to prompt the user to select a file, then read its contents:

// read the contents of a file input
const readInputFile = (inputElement, callback) => {
  const reader = new FileReader();
  reader.onload = () => {
    callback(reader.result)
  };
  reader.readAsText(inputElement.files[0]);
};
// create a file input and destroy it after reading it
export const openFile = (callback) => {
  var el = document.createElement('input');
  el.setAttribute('type', 'file');
  el.style.display = 'none';
  document.body.appendChild(el);
  el.onchange = () => {readInputFile(el, (data) => {
    callback(data)
    document.body.removeChild(el);
  })}
  el.click();
}

Usage:

// prompt the user to select a file and read it
openFile(data => {
    console.log(data)
  })

Examples related to javascript

need to add a class to an element How to make a variable accessible outside a function? Hide Signs that Meteor.js was Used How to create a showdown.js markdown extension Please help me convert this script to a simple image slider Highlight Anchor Links when user manually scrolls? Summing radio input values How to execute an action before close metro app WinJS javascript, for loop defines a dynamic variable name Getting all files in directory with ajax

Examples related to file-io

Python, Pandas : write content of DataFrame into text File Saving response from Requests to file How to while loop until the end of a file in Python without checking for empty line? Getting "java.nio.file.AccessDeniedException" when trying to write to a folder How do I add a resources folder to my Java project in Eclipse Read and write a String from text file Python Pandas: How to read only first n rows of CSV files in? Open files in 'rt' and 'wt' modes How to write to a file without overwriting current contents? Write objects into file with Node.js

Examples related to xmlhttprequest

What is difference between Axios and Fetch? Basic Authentication Using JavaScript XMLHttpRequest module not defined/found loading json data from local file into React JS AngularJS: No "Access-Control-Allow-Origin" header is present on the requested resource Edit and replay XHR chrome/firefox etc? AngularJS Error: Cross origin requests are only supported for protocol schemes: http, data, chrome-extension, https jQuery has deprecated synchronous XMLHTTPRequest Keep getting No 'Access-Control-Allow-Origin' error with XMLHttpRequest Sending a JSON to server and retrieving a JSON in return, without JQuery