How can I pad a value with leading zeros?

Old school way — the "Slice" trick 🎩

Before padStart, you could go:

let num = 42;
let padded = ('0000' + num).slice(-4);  // '0042', no '0' left behind
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Prefer a different length? Just tweak '0000'.

Different tactics for padding and important considerations

Locale variation — Get international 🌐

toLocaleString for fancy formatting:

let num = 5;
let options = { minimumIntegerDigits: 3 };
let padded = num.toLocaleString('en-US', options);  // '005'. Elegant? Yes.
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DIY padding — Play by your rules 😎

Flexibility with your own function:

function zeroPad(num, places) {
  let zero = places - num.toString().length + 1;
  return Array(+(zero > 0 && zero)).join("0") + num; // Rules? What rules?
}
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Dealing with zeroes and space — When zero meets zero 🤝

Some zeroes need their padding, too:

let num = 0;
let padded = num.toString().padStart(2, '0');  // '00'. Double donut 🍩🍩
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Remember, maxLength in padStart equals total desired length, not just party guests (aka padding).

Speed matters — Be logarithmic, be swift ⚡

For performance savvys:

function zeroPad(num, places) {
  let zerosNeeded = places - Math.ceil(Math.log10(num + 1));
  return String(Math.pow(10, Math.max(zerosNeeded, 0)) + num).slice(1); // Who ordered the speed?
}
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Bonus round- Handling compatibility and fallbacks

Easy life hack — Extending prototype 💪

Try adding zeroPad to Number.prototype for easy access, but remember to clean up afterwards in shared environments.

Safe and sound — Checking for padStart 🛡️

Don't let older browsers ruin your game before it begins:

if (!String.prototype.padStart) {
  // Action time! Implement polyfill or fallback. 
}
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Keeping all happy — Browser support 🥳

padStart doesn't play nice with IE. Consider alternatives or polyfills for older browsers.

It's Showtime — Practicals and enhancements

Reusable functions and performance benchmarks can save your day, especially in a zero-padding frenzy.