The snippet library.
Small, practical examples. Search by task or narrow things down below.
Read one character from ASCII text
JavaScript: Use a valid zero-based index to read the first character.
JavaScript✓ Tested
Read the beginning of a text value
JavaScript: Extract or display the first three ASCII characters from a known nonempty string.
JavaScript✓ Tested
Read the final array item with a negative index
JavaScript: at supports negative positions counted from the end.
JavaScript✓ Tested
Read the first collection element
JavaScript: Access index zero only after establishing that the collection is nonempty.
JavaScript✓ Tested
Recover from an expected promise rejection
JavaScript: Return a fallback from catch so later handlers receive an ordinary resolved value.
JavaScript✓ Tested
Remove a Map entry and detect whether it existed
JavaScript: Map.delete returns true only when an entry was present.
JavaScript✓ Tested
Remove duplicate values
Use a JavaScript Set to preserve the first occurrence of each primitive value.
JavaScript✓ Tested
Reorder captured text in a replacement
JavaScript: Use numbered replacement groups to rearrange a known two-part name.
JavaScript✓ Tested
Repeat a fixed number of times
JavaScript: Use a counted loop to print three numbered steps.
JavaScript✓ Tested
Repeat a string a fixed number of times
JavaScript: String.repeat requires a nonnegative finite repetition count.
JavaScript✓ Tested
Repeat while a condition holds
JavaScript: Count down while a positive number remains, updating the loop variable on each iteration.
JavaScript✓ Tested
Replace all literal matches
Replace repeated substrings with JavaScript replaceAll.
JavaScript✓ Tested