Date of yesterday

Results in a string representation of yesterday’s date.

• Use the Date constructor to get the current date.
• Decrement it by one using Date.prototype.getDate() and set the value to the result using Date.prototype.setDate().
• Use Date.prototype.toISOString() to return a string in yyyy-mm-dd format.

const yesterday = () => {
  let d = new Date();
  d.setDate(d.getDate() - 1);
  return d.toISOString().split('T')[0];
};

// EXAMPLE
yesterday(); // 2018-10-17 (if current date is 2018-10-18)

Source

https://www.30secondsofcode.org/js/s/yesterday