85 lines
1.8 KiB
JavaScript
85 lines
1.8 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2022 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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// FUNCTIONS //
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/**
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* Tests if a string starts with a minus sign (`-`).
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*
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* @private
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* @param {string} str - input string
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* @returns {boolean} boolean indicating if a string starts with a minus sign (`-`)
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*/
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function startsWithMinus( str ) {
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return str[ 0 ] === '-';
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}
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/**
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* Returns a string of `n` zeros.
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*
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* @private
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* @param {number} n - number of zeros
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* @returns {string} string of zeros
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*/
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function zeros( n ) {
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var out = '';
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var i;
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for ( i = 0; i < n; i++ ) {
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out += '0';
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}
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return out;
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}
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// MAIN //
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/**
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* Pads a token with zeros to the specified width.
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*
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* @private
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* @param {string} str - token argument
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* @param {number} width - token width
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* @param {boolean} [right=false] - boolean indicating whether to pad to the right
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* @returns {string} padded token argument
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*/
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function zeroPad( str, width, right ) {
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var negative = false;
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var pad = width - str.length;
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if ( pad < 0 ) {
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return str;
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}
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if ( startsWithMinus( str ) ) {
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negative = true;
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str = str.substr( 1 );
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}
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str = ( right ) ?
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str + zeros( pad ) :
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zeros( pad ) + str;
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if ( negative ) {
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str = '-' + str;
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}
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return str;
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}
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// EXPORTS //
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module.exports = zeroPad;
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