filter through js objects using underscore.js

Question

I am trying to filter through this javascript object using underscore.js, but I don't know why it's not working, its meant to find any question value that has "how" in it.

  var questions = [
    {question: "what is your name"},
    {question: "How old are you"},
    {question: "whats is your mothers name"},
    {question: "where do work/or study"},
    ];

var match = _.filter(questions),function(words){ return words === "how"});

alert(match); // its mean to print out -> how old are you?

the full code is here(underscore.js already included): http://jsfiddle.net/7cFbk/

Answer 1

1. You closed the function call with .filter(questions). The last ) shouldn't be there.
2. Filtering works by iterating over the array and calling the function with each element. Here, each element is an object {question: "..."}, not a string.
3. You check for equality, whereas you want to check whether the question string contains a certain string. You even want it case-insensitive.
4. You cannot alert objects. Use the console and console.log instead.

So: http://jsfiddle.net/7cFbk/45/

var questions = [
    {question: "what is your name"},
    {question: "How old are you"},
    {question: "whats is your mothers name"},
    {question: "where do work/or study"},
];

var evens = _.filter(questions, function(obj) {
    // `~` with `indexOf` means "contains"
    // `toLowerCase` to discard case of question string
    return ~obj.question.toLowerCase().indexOf("how");
});

console.log(evens);

Answer 2

Here is a working version:

var questions = [
    {question: "what is your name"},
    {question: "How old are you"},
    {question: "whats is your mothers name"},
    {question: "where do work/or study"},
];

var hasHow = _.filter(questions, function(q){return q.question.match(/how/i)});

console.log(hasHow);

issues fixed:

• Parens were not correctly placed.
• Use console.log instead of alert.
• You should probably use a regexp to find 'how' when iterating over each question.
• _filter iterates over an array. Your array contains objects, and each object contains a question. The function you pass to _filter needs to examine each object in the same way.