es6-generator-preventing-termination.md

ES6 Generator try-finally behavior

1. Generator try-finally prevents termination from return
2. The return value of the generator function is the value that was queued prior to entering the finally clause.

Example adapted from Exploring ES6: Generators. The following two ways are equivalent.

• Invoke .return() on generators:

function* genFunc2() {
    try {
        yield 'first yield';
    } finally {
        yield 'Not done, yet!';
    }
}

> const genObj2 = genFunc2();

> genObj2.next()
{ value: 'first yield', done: false }

> genObj2.return('Result')
{ value: 'Not done, yet!', done: false }

> genObj2.next()
{ value: 'Result', done: true }

• return statement:

function* genFunc2() {
    try {
        yield 'first yield';
        return 'Result';
    } finally {
        yield 'Not done, yet!';
    }
}

> const genObj2 = genFunc2();

> genObj2.next()
Started
{ value: 'first yield', done: false }

> genObj2.next()
{ value: 'Not done, yet!', done: false }

> genObj2.next()
{ value: 'Result', done: true }