JavaScript编译器在Visual Studio中需要“===”而不是“==”

Question

I'm using Visual Studio 2015 and try to update all updates which it needs.

My problem: when I create a new js file, the js compiler would gave me an error eqeqeq (I don't understand what this code means) whenever I use '==' to compare.

Example:

// Declaring a number within a default value
var caret_index = 0;

// Now, js compiler should know 'caret_index' type
// alert(typeof(caret_index)); -> number
// alert($.type(caret_index)); -> number

// So,

// Expected '===' and instead of saw '=='
if (caret_index == 0) {
   // ...
}

That said: You must use '===' in the if condition.

Why? It just needn't cast caret_index to number before comparing to 0 .

Answer 1

It's not Visual Studio, it's your lint settings. If you don't have a .eslintrc.json file in your project root, then create it. Visual Studio will read this to see which rules it should apply. Look for the triple equals rule:

    "triple-equals": [
        false,
        "allow-null-check"
    ]

alternatively, it might be a rule contained in an external file if you have any references under rules directory:

"rulesDirectory" :[]