48 lines
1.2 KiB
JavaScript
48 lines
1.2 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule truncate
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* @flow
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*/
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'use strict';
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var merge = require('merge');
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type truncateOptions = {
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breakOnWords: boolean;
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minDelta: number;
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elipsis: string;
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}
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var defaultOptions = {
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breakOnWords: true,
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minDelta: 10, // Prevents truncating a tiny bit off the end
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elipsis: '...',
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};
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// maxChars (including elipsis)
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var truncate = function(
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str: ?string,
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maxChars: number,
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options: truncateOptions
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): ?string {
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options = merge(defaultOptions, options);
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if (str && str.length &&
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str.length - options.minDelta + options.elipsis.length >= maxChars) {
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str = str.slice(0, maxChars - options.elipsis.length + 1);
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if (options.breakOnWords) {
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var ii = Math.max(str.lastIndexOf(' '), str.lastIndexOf('\n'));
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str = str.slice(0, ii);
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}
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str = str.trim() + options.elipsis;
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}
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return str;
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};
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module.exports = truncate;
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