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Using Lodash truncate

Jun 10, 2022

The truncate function allows you to shorten a string if it is longer than a specifed length. It will shorten the string and replace the last characters of the shortened string with the characters you specify, or the default .... It takes three parameters:

length (number), the maximum length of the string.
omission (string), the string to indicate text is omitted.
separator (RegExp | string), the separator pattern to truncate to.

const _ = require('lodash');

const example = 'Masteringjs.io is a great website to learn JavaScript fundamentals, Mongoose, Vue, and other JavaScript libraries.';

const result = _.truncate(example, {
  length: 39
});

result; // Masteringjs.io is a great website to...

const close = _.truncate(example, {
  length: 36,
  omission: '.',
});

close; // Masteringjs.io is a great website.

Separator

The separator argument is handy for preventing JavaScript from breaking words when truncating. If you pass a separator, JavaScript will truncate at the last instance of separator before length.

const _ = require('lodash');

const example = 'Masteringjs.io is a great website to learn JavaScript fundamentals, mongoose, vue, and other fun JavaScript libraries.';

const short = _.truncate(example, {
  length: 23, // 'Masteringjs.io is a gre'.length
  separator: ' '
});

short; // Masteringjs.io is a...

Because ' ' is the separator, Lodash backtracked and cut off the string at the last space before index 23. Even though index 23 is halfway through "great", truncate() avoided breaking up words.

Using Lodash truncate

Separator

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