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JavaScript: Find out which day was in yesterday

JavaScript Datetime: Exercise-10 with Solution

Write a JavaScript function to calculate 'yesterday day'.

Test Data:
console.log(yesterday('Nov 15, 2014'));
console.log(yesterday('Nov 16, 2015'));
console.log(yesterday('Nov 17, 2016'));
Output :
"Fri Nov 14 2014 00:00:00 GMT+0530 (India Standard Time)"
"Sun Nov 15 2015 00:00:00 GMT+0530 (India Standard Time)"
"Wed Nov 16 2016 00:00:00 GMT+0530 (India Standard Time)"

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Find out which day was in yesterday</title>
</head>
<body>
</body>
</html>

JavaScript Code:

var yesterday =  function(date1){
    var dt = new Date(date1);
  return new Date((dt.setDate(dt.getDate()-1))).toString();
}
console.log(yesterday('Nov 15, 2014'));
console.log(yesterday('Nov 16, 2015'));
console.log(yesterday('Nov 17, 2016'));

Sample Output:

Fri Nov 14 2014 00:00:00 GMT+0530 (India Standard Time)
Sun Nov 15 2015 00:00:00 GMT+0530 (India Standard Time)
Wed Nov 16 2016 00:00:00 GMT+0530 (India Standard Time)

Flowchart:

Flowchart: JavaScript- Find out the last day of a month

Live Demo:

See the Pen JavaScript - Find out which day was in yesterday-date-ex- 10 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

Log the values that are commented out after the console.log statement

function* startGame() {
  const answer = yield 'Do you love JavaScript?';
  if (answer !== 'Yes') {
    return "Oh wow... Guess we're gone here";
  }
  return 'JavaScript loves you back ?';
}

const game = startGame();
console.log(/* 1 */); // Do you love JavaScript?
console.log(/* 2 */); // JavaScript loves you back ?

A generator function "pauses" its execution when it sees the yield keyword. First, we have to let the function yield the string "Do you love JavaScript?", which can be done by calling game.next().value.
Every line is executed, until it finds the first yield keyword. There is a yield keyword on the first line within the function: the execution stops with the first yield! This means that the variable answer is not defined yet!
When we call game.next("Yes").value, the previous yield is replaced with the value of the parameters passed to the next() function, "Yes" in this case. The value of the variable answer is now equal to "Yes". The condition of the if-statement returns false, and JavaScript loves you back ? gets logged.

Ref: https://bit.ly/3jFRBje