85 lines
1.9 KiB
JavaScript
85 lines
1.9 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 clampIndex = require( './../../../base/clamp-index' );
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var wrapIndex = require( './../../../base/wrap-index' );
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// MAIN //
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/**
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* Returns an index given an index mode.
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*
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* @param {integer} idx - index
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* @param {NonNegativeInteger} max - maximum index
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* @param {string} mode - specifies how to handle an index outside the interval `[0,max]`
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* @throws {RangeError} index out-of-bounds
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* @returns {integer} index
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*
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* @example
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* var idx = ind( 2, 9, 'clamp' );
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* // returns 2
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*
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* idx = ind( 10, 9, 'clamp' );
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* // returns 9
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*
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* idx = ind( -1, 9, 'clamp' );
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* // returns 0
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*
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* @example
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* var idx = ind( 2, 9, 'wrap' );
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* // returns 2
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*
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* idx = ind( 10, 9, 'wrap' );
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* // returns 0
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*
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* idx = ind( -1, 9, 'wrap' );
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* // returns 9
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*
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* @example
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* var idx = ind( 2, 9, 'throw' );
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* // returns 2
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*
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* idx = ind( 10, 9, 'throw' );
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* // throws <RangeError>
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*
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* idx = ind( -1, 9, 'throw' );
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* // throws <RangeError>
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*/
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function ind( idx, max, mode ) {
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if ( mode === 'clamp' ) {
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return clampIndex( idx, max );
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}
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if ( mode === 'wrap' ) {
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return wrapIndex( idx, max );
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}
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if ( idx < 0 || idx > max ) {
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throw new RangeError( 'invalid argument. Index must be on the interval: [0,' + max + ']. Value: `' + idx + '`.' );
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}
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return idx;
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}
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// EXPORTS //
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module.exports = ind;
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