TypeScript - Compiler Behavior - tsconfig.json - noImplicitAny

Our current tsconfig.json is:

{

"compilerOptions": {

/* Basic Options */

"target": "es5",

"module": "commonjs",

"strict": true,

"esModuleInterop": true,

"noImplicitAny":false,

"sourceMap":true,

"noEmitOnError": true

},

"exclude":[

"node_modules"

]

}

We have one more compiler option which we have not covered before. It is noImplicitAny.

Considering our file: city-App.ts:

let myCity:string = "Hyderabad";

let cityElevation: number = 505;

// added below

let cityArea;

cityArea = "Not Available";

Since, we did not specify a type for cityArea variable. Hence, it has received a type of any - although we did not specify a datatype for it.

Now, in the file tsconfig.json - If I set the compilerOptions - noImplicitAny to true.

"noImplicitAny":true,

Due to this, now, if we run tsc. We should receive a compiler warning. But, in general it is better to leave it as false.