67 lines
1.7 KiB
Markdown
67 lines
1.7 KiB
Markdown
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# locate-character
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Get the line and column number of a particular character in a string.
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## Installation
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`npm install locate-character`, or get it from [unpkg.com/locate-character](https://unpkg.com/locate-character).
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## Usage
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To search for a particular character, using the index or a search string, use `locate`:
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```js
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import { locate } from 'locate-character';
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const sample = `
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A flea and a fly in a flue
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Were imprisoned, so what could they do?
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Said the fly, "let us flee!"
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"Let us fly!" said the flea.
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So they flew through a flaw in the flue.
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`.trim();
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// Using a character index
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const index = sample.indexOf('fly');
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locate(sample, index);
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// -> { line: 0, column: 13, character: 13 }
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// Using the string itself
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locate(sample, 'fly');
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// -> { line: 0, column: 13, character: 13 }
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// Using the string with a start index
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locate(sample, 'fly', { startIndex: 14 });
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// -> { line: 2, column: 9, character: 76 }
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```
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If you will be searching the same string repeatedly, it's much faster if you use `getLocator`:
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```js
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import { getLocator } from 'locate-character';
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const locate = getLocator(sample);
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let location = locate(13);
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// -> { line: 0, column: 13, character: 13 }
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location = locate('fly', { startIndex: location.character + 1 });
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// -> { line: 2, column: 9, character: 76 }
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location = locate('fly', { startIndex: location.character + 1 });
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// -> { line: 3, column: 8, character: 104 }
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```
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In some situations (for example, dealing with sourcemaps), you need one-based line numbers:
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```js
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getLocator(sample, { offsetLine: 1 });
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locate(sample, { offsetLine: 1 });
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```
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There's also an `offsetColumn` option which is less useful in real-world situations.
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## License
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MIT
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