Data Wrangling with JavaScript

appendix a: JavaScript cheat sheet

Updates

You can find an updated and evolving version of this cheat sheet online at http://jscheatsheet.the-data-wrangler.com.

Logging

Logging is your best friend. It’s the easiest way to inspect and check your data:

console.log("Your logging here"); // General text logging for debugging.

const arr = [1, 2, 3];            // Your data.
console.log(arr);

console.trace();                  // Show callstack for current function.

Objects

let o = { A: 1, B: 2 }; // Your data let v1 = o["A"]; // Extract field value let v2 = o.A; o["A"] = 3; // Set field value o.A = 3; delete o["A"]; // Delete a field value delete o.A; let c = Object.assign({}, o); // Clone an object let ovr = { /* ... */ }; let c = Object.assign({}, o, ovr); // Clone and override ...