73 lines
2.3 KiB
JavaScript
73 lines
2.3 KiB
JavaScript
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import { filter, filterRegExp } from '../../utils/array.js';
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import { maxArgumentCount } from '../../utils/function.js';
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import { factory } from '../../utils/factory.js';
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var name = 'filter';
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var dependencies = ['typed'];
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export var createFilter = /* #__PURE__ */factory(name, dependencies, _ref => {
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var {
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typed
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} = _ref;
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/**
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* Filter the items in an array or one dimensional matrix.
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*
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* Syntax:
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*
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* math.filter(x, test)
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*
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* Examples:
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*
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* function isPositive (x) {
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* return x > 0
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* }
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* math.filter([6, -2, -1, 4, 3], isPositive) // returns [6, 4, 3]
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*
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* math.filter(["23", "foo", "100", "55", "bar"], /[0-9]+/) // returns ["23", "100", "55"]
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*
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* See also:
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*
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* forEach, map, sort
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*
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* @param {Matrix | Array} x A one dimensional matrix or array to filter
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* @param {Function | RegExp} test
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* A function or regular expression to test items.
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* All entries for which `test` returns true are returned.
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* When `test` is a function, it is invoked with three parameters:
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* the value of the element, the index of the element, and the
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* matrix/array being traversed. The function must return a boolean.
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* @return {Matrix | Array} Returns the filtered matrix.
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*/
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return typed('filter', {
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'Array, function': _filterCallback,
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'Matrix, function': function MatrixFunction(x, test) {
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return x.create(_filterCallback(x.toArray(), test));
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},
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'Array, RegExp': filterRegExp,
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'Matrix, RegExp': function MatrixRegExp(x, test) {
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return x.create(filterRegExp(x.toArray(), test));
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}
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});
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});
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/**
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* Filter values in a callback given a callback function
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* @param {Array} x
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* @param {Function} callback
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* @return {Array} Returns the filtered array
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* @private
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*/
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function _filterCallback(x, callback) {
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// figure out what number of arguments the callback function expects
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var args = maxArgumentCount(callback);
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return filter(x, function (value, index, array) {
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// invoke the callback function with the right number of arguments
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if (args === 1) {
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return callback(value);
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} else if (args === 2) {
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return callback(value, [index]);
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} else {
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// 3 or -1
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return callback(value, [index], array);
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}
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});
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}
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