JavaScript - Check string with an array

Question

This piece of code should return hits = ["Heather, "Heather", "Heather"] but it doesn't. I'm not quite sure what I am doing wrong.

var text = ["Heather", "kfdjsalfjdai", "fdjafhjdksafh", "Heather", "Heather", "fjdiafjdoisfhoids"];
var myName = "Heather";
var hits = [];
for(var i = 0; i < text.length; i++) {
 if (text[i] === myName[i]) {
 for(var j = i; j < (myName.length + i); j++); {
 hits.push(text[j]);
 }
 }
}

• elclanrs: This functionality is builtin already var hits = text.filter(function(s){return s===myName})

Answer 1

You can use array filter function:

var hits = text.filter(function (obj) {
 return obj === myName;
});

Snippet

var text = ["Heather", "kfdjsalfjdai", "fdjafhjdksafh", "Heather", "Heather", "fjdiafjdoisfhoids"];
var myName = "Heather";
var hits = text.filter(function (obj) {
 return obj === myName;
});
console.log(hits);

• Cake: I haven't had that function yet though. Could you help me solve this problem by using a 'simple' for loop?
• Sterling Archer: Mandatory ES6 syntax: var hits = text.filter(obj => obj === myName);
• Sterling Archer: Why would a legacy browser support modern technology? Microsoft is dropping IE10 support soon as is. Modern technology requires modern browsers.
• Madara's Ghost: @PraveenKumar You know that not all browsers support Array.prototype.filter() either, right? IE8 doesn't support it. So now what, fall back to for loops? We move on. And the quicker we as a development community forget about the atrocities of the past, the better.
• user1596138: /me makes note to never respond to this guy cause he won't listen unless you are a mod

Answer 2

Obligatory use this library answer. Here I use lodash:

var text = ["Heather", "kfdjsalfjdai", "fdjafhjdksafh", "Heather", "Heather", "something"],
 myName = "Heather";
var hits = _.filter(text, _.matches([myName]);

Explanation on what's happening because this isn't intuitive at all. _.filter does the same thing as Array.prototype.filter except it's faster. You can run your own tests below to get an idea:

https://jsperf.com/array-filter-vs-lodash-filter-without-bias/2

The explanation I've heard is that traditional array operations implemented by lodash (map, reduce, filter, etc.) don't have to follow the implementation as detailed by the spec.

Anyways, _.filter takes two arguments: a collection (array or object) and function which returns true or false. If true, it'll return the item.

_.matches is a convenience function which returns a function that takes an argument and matches against the contents of the provided collection.

You could write the above another way:

var hits = _.filter(text, function(str) {
 return str === myName
});

In lodash, we create functions all the time that basically executes an equality check. _.matches is just a convenience function to create equality check function.

Answer 3

Check against myName variable.

var text = ["Heather", "kfdjsalfjdai", "fdjafhjdksafh", "Heather", "Heather", 
 "fsomething"];
var myName = "Heather";
var hits = [];
for(var i = 0; i < text.length; i++) {
 if (text[i] === myName) { 
 hits.push(text[i]); 
 }
}
console.log(hits);

Here is a working sample

• Cake: Perfect, this is exactly what I needed.
• Praveen Kumar Purushothaman: @Shyju Could be a reason: There's a built in function, but not sure why reinventing the wheel. :)

Answer 4

text[i] will never === myName[i], because text is an array of strings, whereas myName is just one string. So for example, text[1] === "Heather", whereas myName[1] === "H". Any index of myName will just return one character.