29 lines
1.2 KiB
Markdown
29 lines
1.2 KiB
Markdown
---
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title: truncateStringAtWhitespace
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tags: string,intermediate
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firstSeen: 2020-10-19T11:11:16+03:00
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lastUpdated: 2020-10-21T21:17:45+03:00
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---
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Truncates a string up to specified length, respecting whitespace when possible.
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- Determine if `String.prototype.length` is greater or equal to `lim`. If not, return it as-is.
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- Use `String.prototype.slice()` and `String.prototype.lastIndexOf()` to find the index of the last space below the desired `lim`.
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- Use `String.prototype.slice()` to appropriately truncate `str` based on `lastSpace`, respecting whitespace if possible and appending `ending` at the end.
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- Omit the third argument, `ending`, to use the default ending of `'...'`.
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```js
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const truncateStringAtWhitespace = (str, lim, ending = '...') => {
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if (str.length <= lim) return str;
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const lastSpace = str.slice(0, lim - ending.length + 1).lastIndexOf(' ');
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return str.slice(0, lastSpace > 0 ? lastSpace : lim - ending.length) + ending;
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};
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```
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```js
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truncateStringAtWhitespace('short', 10); // 'short'
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truncateStringAtWhitespace('not so short', 10); // 'not so...'
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truncateStringAtWhitespace('trying a thing', 10); // 'trying...'
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truncateStringAtWhitespace('javascripting', 10); // 'javascr...'
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```
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