CLiown CLiown - 1 year ago 101
Javascript Question

Remove occurrences of duplicate words in a string

Take the following string as an example:

var string = "spanner, span, spaniel, span";

From this string I would like to find the duplicate words, remove all the duplicates keeping one occurrence of the word in place and then output the revised string.

Which in this example would be:

var string = "spanner, span, spaniel";

I've setup a jsFiddle for testing:

Note that the order of the words in the string is not consistent, neither is the length of each string so a regex isn't going to do the job here I don't think. I'm thinking something along the lines of splitting the string into an array? But I'd like it to be as light on the client as possible and super speedy...

Answer Source

How about something like this?

split the string, get the array, filter it to remove duplicate items, join them back.

var uniqueList=string.split(',').filter(function(item,i,allItems){
    return i==allItems.indexOf(item);



For non supporting browsers you can tackle it by adding this in your js.

See Filter

if (!Array.prototype.filter)
  Array.prototype.filter = function(fun /*, thisp*/)
    "use strict";

    if (this == null)
      throw new TypeError();

    var t = Object(this);
    var len = t.length >>> 0;
    if (typeof fun != "function")
      throw new TypeError();

    var res = [];
    var thisp = arguments[1];
    for (var i = 0; i < len; i++)
      if (i in t)
        var val = t[i]; // in case fun mutates this
        if (, val, i, t))

    return res;
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