49 lines
914 B
JavaScript
49 lines
914 B
JavaScript
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'use strict';
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var filter = require('through2-filter').obj;
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var stringify = require("json-stable-stringify");
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var ES6Set;
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if (typeof global.Set === 'function') {
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ES6Set = global.Set;
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} else {
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ES6Set = function() {
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this.keys = [];
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this.has = function(val) {
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return this.keys.indexOf(val) !== -1;
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},
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this.add = function(val) {
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this.keys.push(val);
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}
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}
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}
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function prop(propName) {
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return function (data) {
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return data[propName];
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};
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}
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module.exports = unique;
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function unique(propName, keyStore) {
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keyStore = keyStore || new ES6Set();
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var keyfn = stringify;
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if (typeof propName === 'string') {
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keyfn = prop(propName);
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} else if (typeof propName === 'function') {
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keyfn = propName;
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}
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return filter(function (data) {
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var key = keyfn(data);
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if (keyStore.has(key)) {
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return false;
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}
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keyStore.add(key);
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return true;
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});
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}
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