generator.throw

generator.throw

The throw() method resumes the execution of a generator by throwing an error into it and returns an object with two properties done and value.

Syntax

gen.throw(exception)

Parameters

exceptionThe exception to throw. For debugging purposes, it is useful to make it an instanceofError.

Return value

An Object with two properties:

• done (boolean)

Examples

Using throw()

The following example shows a simple generator and an error that is thrown using the throw method. An error can be caught by a try...catch block as usual.

function* gen() {
  while(true) {
    try {
       yield 42;
    } catch(e) {
      console.log('Error caught!'
    }
  }
}

var g = gen(
g.next(
// { value: 42, done: false }
g.throw(new Error('Something went wrong')
// "Error caught!"
// { value: 42, done: false }

Specifications

Browser compatibility

See also

• function*

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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Generator/throw