Question

I’m following this lesson: http://nathansjslessons.appspot.com/lesson?id=1040

These are the instructions:

Define a function named applyTest that takes two arguments, a function
f and an input x. Your function should return a list that contains x,
the function f on the input x, and the function f on the input 0.

This is what I’ve done so far:

var f = function (x) {
    return x + 2;
};

var g = function (x) {
    return x * 3;
};

var applyTest = function (f, x) {
    return [x, f(2), f(0)];
};

and this is what JSLint is saying:

PASSED No JSLint errors
PASSED applyTest is a function
PASSED applyTest(f, 1)[0] === 1
FAILED applyTest(f, 1)[1] === 3 (4 !== 3)
PASSED applyTest(f, 1)[2] === 2
PASSED applyTest(f, 2).compareArrays([2, 4, 2])
FAILED applyTest(g, 3).compareArrays([3, 9, 0])

How do I correct that code in order to pass the lesson?

Answer 1

bad

var applyTest = function (f, x) {
    return [x, f(2), f(0)];
};

good

var applyTest = function (f, x) {
    return [x, f(x), f(0)];
};