81 lines
1.5 KiB
JavaScript
81 lines
1.5 KiB
JavaScript
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/**
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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( './../../is-string' ).isPrimitive;
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// VARIABLES //
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// Character codes:
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var ZERO = 48;
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var NINE = 57;
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// MAIN //
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/**
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* Tests whether a string contains only numeric digits.
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*
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* @param {*} x - value to test
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* @returns {boolean} boolean indicating if a string contains only numeric digits
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*
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* @example
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* var out = isDigitString( '0123456789' );
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* // returns true
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*
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* @example
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* var out = isDigitString( '0xffffff' );
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* // returns false
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*
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* @example
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* var out = isDigitString( '' );
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* // returns false
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*
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* @example
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* var out = isDigitString( 123 );
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* // returns false
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*/
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function isDigitString( x ) {
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var len;
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var ch;
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var i;
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if ( !isString( x ) ) {
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return false;
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}
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len = x.length;
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if ( len === 0 ) {
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return false;
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}
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for ( i = 0; i < len; i++ ) {
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ch = x.charCodeAt( i );
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if ( ch < ZERO || ch > NINE ) {
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return false;
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}
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}
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return true;
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}
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// EXPORTS //
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module.exports = isDigitString;
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