The snippet library.
Small, practical examples. Search by task or narrow things down below.
Add calendar days in UTC
JavaScript: Use UTC date setters to cross month boundaries without local daylight-saving effects.
JavaScript✓ Tested
Build a URL query string from values
JavaScript: URLSearchParams handles query escaping and repeated parameter appends.
JavaScript✓ Tested
Build an object from key-value entries
JavaScript: Object.fromEntries converts an iterable of pairs into ordinary own properties.
JavaScript✓ Tested
Calculate a page count with ceiling division
JavaScript: Use Math.ceil for a nonnegative item count and a positive page size.
JavaScript✓ Tested
Calculate a simple total
JavaScript: Multiply a unit price by a quantity, then add a delivery fee.
JavaScript✓ Tested
Calculate differences between adjacent readings
JavaScript: Slice off the first value and compare each remaining value with its predecessor.
JavaScript✓ Tested
Calculate integers beyond Number’s precise range
JavaScript: Use BigInt operands together to avoid precision loss.
JavaScript✓ Tested
Call a library function
JavaScript: Use a standard absolute-value function with a small negative number.
JavaScript✓ Tested
Check array membership with includes
JavaScript: includes uses SameValueZero comparison, which also matches NaN.
JavaScript✓ Tested
Check for a substring
Perform a case-sensitive JavaScript substring check.
JavaScript✓ Tested
Check whether a value is a safe integer
JavaScript: Number.isSafeInteger also checks the exact-integer range supported by Number.
JavaScript✓ Tested
Check whether any item matches
JavaScript: some stops once a predicate succeeds.
JavaScript✓ Tested