45 lines
1.5 KiB
JavaScript
45 lines
1.5 KiB
JavaScript
'use strict';
|
|
|
|
var $TypeError = require('es-errors/type');
|
|
|
|
var CreateIterResultObject = require('es-abstract/2024/CreateIterResultObject');
|
|
var IsCallable = require('es-abstract/2024/IsCallable');
|
|
var Type = require('es-abstract/2024/Type');
|
|
|
|
var SLOT = require('internal-slot');
|
|
|
|
module.exports = function GeneratorStart(generator, closure) {
|
|
SLOT.assert(generator, '[[GeneratorState]]');
|
|
SLOT.assert(generator, '[[GeneratorContext]]');
|
|
SLOT.assert(generator, '[[GeneratorBrand]]');
|
|
SLOT.assert(generator, '[[Sentinel]]'); // our userland slot
|
|
SLOT.assert(generator, '[[CloseIfAbrupt]]'); // our second userland slot
|
|
|
|
if (!IsCallable(closure) || closure.length !== 0) {
|
|
throw new $TypeError('`closure` must be a function that takes no arguments');
|
|
}
|
|
|
|
var sentinel = SLOT.get(closure, '[[Sentinel]]');
|
|
if (Type(sentinel) !== 'Object') {
|
|
throw new $TypeError('`closure.[[Sentinel]]` must be an object');
|
|
}
|
|
SLOT.set(generator, '[[GeneratorContext]]', function () { // steps 2-5
|
|
try {
|
|
var result = closure();
|
|
if (result === sentinel) {
|
|
SLOT.set(generator, '[[GeneratorState]]', 'completed');
|
|
SLOT.set(generator, '[[GeneratorContext]]', null);
|
|
return CreateIterResultObject(void undefined, true);
|
|
}
|
|
SLOT.set(generator, '[[GeneratorState]]', 'suspendedYield');
|
|
return CreateIterResultObject(result, false);
|
|
} catch (e) {
|
|
SLOT.set(generator, '[[GeneratorState]]', 'completed');
|
|
SLOT.set(generator, '[[GeneratorContext]]', null);
|
|
throw e;
|
|
}
|
|
});
|
|
|
|
SLOT.set(generator, '[[GeneratorState]]', 'suspendedStart'); // step 6
|
|
};
|