forked from hero/www_hero
135 lines
4.4 KiB
Markdown
135 lines
4.4 KiB
Markdown
didYouMean.js - A simple JavaScript matching engine
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===================================================
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[Available on GitHub](https://github.com/dcporter/didyoumean.js).
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A super-simple, highly optimized JS library for matching human-quality input to a list of potential
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matches. You can use it to suggest a misspelled command-line utility option to a user, or to offer
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links to nearby valid URLs on your 404 page. (The examples below are taken from a personal project,
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my [HTML5 business card](http://dcporter.aws.af.cm/me), which uses didYouMean.js to suggest correct
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URLs from misspelled ones, such as [dcporter.aws.af.cm/me/instagarm](http://dcporter.aws.af.cm/me/instagarm).)
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Uses the [Levenshtein distance algorithm](https://en.wikipedia.org/wiki/Levenshtein_distance).
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didYouMean.js works in the browser as well as in node.js. To install it for use in node:
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```
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npm install didyoumean
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```
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Examples
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--------
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Matching against a list of strings:
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```
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var input = 'insargrm'
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var list = ['facebook', 'twitter', 'instagram', 'linkedin'];
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console.log(didYouMean(input, list));
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> 'instagram'
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// The method matches 'insargrm' to 'instagram'.
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input = 'google plus';
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console.log(didYouMean(input, list));
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> null
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// The method was unable to find 'google plus' in the list of options.
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```
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Matching against a list of objects:
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```
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var input = 'insargrm';
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var list = [ { id: 'facebook' }, { id: 'twitter' }, { id: 'instagram' }, { id: 'linkedin' } ];
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var key = 'id';
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console.log(didYouMean(input, list, key));
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> 'instagram'
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// The method returns the matching value.
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didYouMean.returnWinningObject = true;
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console.log(didYouMean(input, list, key));
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> { id: 'instagram' }
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// The method returns the matching object.
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```
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didYouMean(str, list, [key])
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----------------------------
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- str: The string input to match.
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- list: An array of strings or objects to match against.
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- key (OPTIONAL): If your list array contains objects, you must specify the key which contains the string
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to match against.
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Returns: the closest matching string, or null if no strings exceed the threshold.
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Options
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-------
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Options are set on the didYouMean function object. You may change them at any time.
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### threshold
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By default, the method will only return strings whose edit distance is less than 40% (0.4x) of their length.
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For example, if a ten-letter string is five edits away from its nearest match, the method will return null.
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You can control this by setting the "threshold" value on the didYouMean function. For example, to set the
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edit distance threshold to 50% of the input string's length:
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```
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didYouMean.threshold = 0.5;
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```
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To return the nearest match no matter the threshold, set this value to null.
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### thresholdAbsolute
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This option behaves the same as threshold, but instead takes an integer number of edit steps. For example,
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if thresholdAbsolute is set to 20 (the default), then the method will only return strings whose edit distance
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is less than 20. Both options apply.
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### caseSensitive
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By default, the method will perform case-insensitive comparisons. If you wish to force case sensitivity, set
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the "caseSensitive" value to true:
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```
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didYouMean.caseSensitive = true;
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```
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### nullResultValue
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By default, the method will return null if there is no sufficiently close match. You can change this value here.
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### returnWinningObject
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By default, the method will return the winning string value (if any). If your list contains objects rather
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than strings, you may set returnWinningObject to true.
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```
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didYouMean.returnWinningObject = true;
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```
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This option has no effect on lists of strings.
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### returnFirstMatch
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By default, the method will search all values and return the closest match. If you're simply looking for a "good-
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enough" match, you can set your thresholds appropriately and set returnFirstMatch to true to substantially speed
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things up.
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License
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-------
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didYouMean copyright (c) 2013-2014 Dave Porter.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License
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[here](http://www.apache.org/licenses/LICENSE-2.0).
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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