6 examples of 'check duplicate values in array javascript' in JavaScript

53
function testForDuplicates(obj, key, dups) {
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    test(wrap(key) + ' has no duplicate', function() {
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        var id = key.toUpperCase(),
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            exists = id in dups;
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        if (exists) {
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            dups[id].push(key);
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        } else {
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            dups[id] = [ key ];
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        }
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        assert.ok(!exists, dups[id].join(', '));
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    });
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}

52
function horribleDuplicates (array) {
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    for (var i = 0; i < array.length; i++) {
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        for (var j = 0; j < array.length; j++) {
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            if (array[i] == array[j]) {
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                return true
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            }
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        }
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    }
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    return false
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}

270
export function getDuplicateNames(indexableArray: { name: string }[]): string[] {
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  const seen: { [name: string]: number } = {};
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  const duplicates: string[] = [];
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  indexableArray.forEach((element: { name: string }) => {
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    const { name } = element;
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    const count = seen[name] || 0;
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    if (count === 1) {
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      duplicates.push(name);
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    }
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    seen[name] = count + 1;
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  });
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  return duplicates;
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}

64
function duplicateArray(array) {
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  return array.clone ? array.clone() : new Array(array.length);
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}

30
function duplicateArray(arr) {
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  var newArr = [];
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  for(var i=0, arrSize=arr.length; i

108
function verify_distinct(values) {
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    var arr, i, j, k, N;
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    if (values instanceof Array) {
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        arr = values;
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    } else if (values instanceof Object) {
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        arr = [];
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        for (k in values) {
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            arr.push(values[k]);
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        }
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    } else {
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        throw "verify_distinct: Invalid argument.";
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    }
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    for (i = 0, N = arr.length; i < N; ++i) {
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        for (j = 0; j < i; ++j) {
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            if (arr[i] === arr[j]) {
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                return false;
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            }
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        }
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    }
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    return true;
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}