jquery - JavaScript IF statement boolean strict

Question

I am setting a mode in a script by passing a "truthy" boolean to a function. In the function a simple if statement checks if the param is true or false. I sometimes pass it as a string or a bool which has always worked, but for some reason it isn't for this:

setMode: function(Setting) {    
    if (Setting) {
        console.log('Enabling mode');
    } else {
        console.log('Disabling mode');
    }
}

For example when I pass it a string 'false' and log Setting to console, the console says false, yet the if statement thinks it's true.

I have to add this to the start of the function for it to work:

if (typeof Setting == 'string') { Setting = (Setting == "true"); }

An example of it in use:

var inverted = $('INPUT[name="Mode"]').prop('checked');
app.setMode(inverted);

and another:

var mode = localStorage.getItem('Mode');
this.setMode(mode);

It's so bizarre since I've done this type of thing for years yet it's only starting now. Maybe because I'm using localStorage and .prop?

Answer 1

If you try to log 'false' it is obvious that console logs false(it is a string) and that the if statement sees true, because a not-empty string is a true boolean value.

If you want to check if the string is "true" or "false" you have to do it with normal operators. So you could add this line at the beginning of your function:

Setting = (typeof Setting === 'string') ? Setting === "true" : Setting;