Annotating Types

Annotating declarations and casts

Introduction

The compiler recognizes @type annotations in two contexts: declarations and casts.

Details

Function declarations

/** @type {function():string} */
function f() {return 'str'}

Variable declarations

/** @type {string} */
var x = 'fruit';

or

    var /** @type {string} */ x = 'fruit';

Property declarations

    /** @type {string} */
    x.prop = 'fruit';

or

    var x = {
      /** @type {string} */
      prop : 'fruit'
    };

Catch declarations

try { 
  ... 
} catch (/** @type {string} */ e) {
  ...
}

Type Casts

Type cast precede a parenthesized expression.

    var x = /** @type {string} */ (fruit);