66 lines
1.7 KiB
JavaScript
66 lines
1.7 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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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 at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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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*/
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'use strict';
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// MODULES //
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var isString = require( '@stdlib/assert/is-string' ).isPrimitive;
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var replace = require( './../../replace' );
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var format = require( './../../format' );
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// VARIABLES //
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// The following regular expression should suffice to polyfill (most?) all environments.
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var RE = /^[\u0020\f\n\r\t\v\u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff]+/;
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// MAIN //
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/**
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* Trims whitespace characters from the beginning of a string.
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*
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* @param {string} str - input string
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* @throws {TypeError} must provide a string primitive
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* @returns {string} trimmed string
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*
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* @example
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* var out = ltrim( ' Whitespace ' );
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* // returns 'Whitespace '
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*
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* @example
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* var out = ltrim( '\t\t\tTabs\t\t\t' );
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* // returns 'Tabs\t\t\t'
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*
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* @example
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* var out = ltrim( '\n\n\nNew Lines\n\n\n' );
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* // returns 'New Lines\n\n\n'
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*/
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function ltrim( str ) {
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if ( !isString( str ) ) {
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throw new TypeError( format( 'invalid argument. Must provide a string. Value: `%s`.', str ) );
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}
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return replace( str, RE, '' );
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}
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// EXPORTS //
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module.exports = ltrim;
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