char-props

Utility for looking up line and column of a character at a given index and vice versa

npm install char-props
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char-props Donate on Gittip

Utility for looking up line and column of a character at a given index and vice versa.

Getting Started

Install the module with: npm install charProps

Documentation

// charProps is a function which invokes the Indexer constructor

// Indexer JSDoc
/**
 * Indexer constructor (takes index and performs pre-emptive caching)
 * @constructor
 * @param {String} input Content to index
 */

// Indexer.lineAt JSDoc
/**
 * Get the line of the character at a certain index
 * @param {Number} index Index of character to retrieve line of
 * @param {Object} [options] Options to use for search
 * @param {Number} [options.minLine=0] Minimum line for us to search on
 * TODO: The following still have to be built/implemented
 * @param {Number} [options.maxLine=lines.length] Maximum line for us to search on
 * @param {String} [options.guess="average"] Affects searching pattern -- can be "high", "low", or "average" (linear top-down, linear bottom-up, or binary)
 * @returns {Number} Line number of character
 */

// Indexer.columnAt JSDoc
/**
 * Get the column of the character at a certain index
 * @param {Number} index Index of character to retrieve column of
 * @returns {Number} Column number of character
 */

// Indexer.indexAt JSDoc
/**
 * Get the index of the character at a line and column
 * @param {Object} params Object containing line and column
 * @param {Number} params.line Line of character
 * @param {Number} params.column Column of character
 * @returns {Number} Index of character
 */

// Indexer.charAt JSDoc
/**
 * Get the character at a line and column
 * @param {Object} params Object containing line and column
 * @param {Number} params.line Line of character
 * @param {Number} params.column Column of character
 * @returns {String} Character at specified location
 */

Examples

Initial load

var charProps = require('char-props'),
    jquerySrc = fs.readFileSync('jquery.js', 'utf8');

// Load jQuery into charProps
var jqueryProps = charProps(jquerySrc);

lineAt usage

// Look up line of character at index 42
jqueryProps.lineAt(42);

columnAt usage

// Look up column of character at index 88
jqueryProps.columnAt(88);

indexAt usage

// Look up the index of a character at line 9000, column 1
jqueryProps.indexAt({'line': 9000, 'column': 1});

charAt usage

// Get the character at line 20, column 20
jqueryProps.charAt({'line': 20, 'column': 20});

lineAt advanced usage

// Look up line of character at index 9001 with a minimum line of 99
jqueryProps.lineAt(9001, {'minLine': 99});

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint your code via grunt and test via vows.

License

Copyright (c) 2012 Todd Wolfson Licensed under the MIT license.

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