TypeScript: Convert a bool to string value

问题:

I have a really simple issue, I can't get to convert a simple boolean to a string value in TypeScript.

I have been roaming throught documentation and I could not find anything helpful and of course I tried to use the toString() method but it does not seem to be implemented on bool.

---

Edit: I have almost no JavaScript knowledge and came to TypeScript with a C#/Java background.

回答1:

This is either a bug in TypeScript or a concious design decision, but you can work around it using:

var myBool: bool = true;
var myString: string = String(myBool);
alert(myString);

In JavaScript booleans override the toString method, which is available on any Object (pretty much everything in JavaScript inherits from Object), so...

var myString: string = myBool.toString();

... should probably be valid.

There is also another work around for this, but I personally find it a bit nasty:

var myBool: bool = true;
var myString: string = <string><any> myBool;
alert(myString);

回答2:

For those looking for an alternative, another way to go about this is to use a template literal like the following:

const booleanVal = true;
const stringBoolean = `${booleanVal}`;

The real strength in this comes if you don't know for sure that you are getting a boolean value. Although in this question we know it is a boolean, thats not always the case, even in TypeScript(if not fully taken advantage of).

回答3:

One approach is to use the Ternary operator:

myString = myBool? "true":"false";

回答4:

This if you have to handle null values too:

stringVar = boolVar===null? "null" : (boolVar?"true":"false");