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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.

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Using Lodash truncate

Separator

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