es-iterator-helpers
Version:
An ESnext spec-compliant iterator helpers shim/polyfill/replacement that works as far down as ES3.
350 lines (284 loc) • 12.7 kB
JavaScript
;
var defineProperties = require('define-properties');
var test = require('tape');
var callBind = require('call-bind');
var functionsHaveNames = require('functions-have-names')();
var forEach = require('for-each');
var debug = require('object-inspect');
var v = require('es-value-fixtures');
var hasSymbols = require('has-symbols/shams')();
var hasPropertyDescriptors = require('has-property-descriptors')();
var mockProperty = require('mock-property');
var index = require('../Iterator.zipKeyed');
var impl = require('../Iterator.zipKeyed/implementation');
var from = require('../Iterator.from/polyfill')();
var testIterator = require('./helpers/testIterator');
var isEnumerable = Object.prototype.propertyIsEnumerable;
module.exports = {
tests: function (zipKeyed, name, t) {
t['throws'](
function () { return new zipKeyed(); }, // eslint-disable-line new-cap
TypeError,
'`' + name + '` itself is not a constructor'
);
t['throws'](
function () { return new zipKeyed({}); }, // eslint-disable-line new-cap
TypeError,
'`' + name + '` itself is not a constructor, with an argument'
);
forEach(v.primitives, function (primitive) {
t['throws'](
function () { zipKeyed(primitive); },
TypeError,
debug(primitive) + ' is not an Object'
);
if (primitive != null) {
t['throws'](
function () { zipKeyed({ a: primitive }); },
TypeError,
'key "a" on iterables object is ' + debug(primitive) + ' which is not an iterable Object'
);
}
});
forEach(v.objects, function (nonIterator) {
t.doesNotThrow(function () { zipKeyed({ a: nonIterator }); }, 'does not throw until `.next()`');
t['throws'](
function () { zipKeyed({ a: nonIterator }).next(); },
TypeError,
'key "a" on iterables object is ' + debug(nonIterator) + ' which is not an iterable Object'
);
});
t.test('actual iteration', { skip: !hasSymbols }, function (st) {
forEach(v.nonFunctions, function (nonFunction) {
if (nonFunction != null) {
var badIterable = {};
badIterable[Symbol.iterator] = nonFunction;
st['throws'](
function () { zipKeyed({ a: [], b: badIterable, c: [] }).next(); },
TypeError,
'key "b" on iterables object is ' + debug(badIterable) + ' is not a function'
);
}
});
forEach(v.strings, function (string) {
st['throws'](
function () { zipKeyed({ a: string }); },
TypeError,
'key "a" on iterables object is an iterable primitive, but non-objects are not considered iterable'
);
});
st.test('real iterators', { skip: !hasSymbols }, function (s2t) {
var iter = [['a', 1], ['b', 2]][Symbol.iterator]();
var iterator = zipKeyed({ a: iter, b: ['a', 3], c: ['b', 4] });
testIterator(
iterator,
[
{ __proto__: null, a: ['a', 1], b: 'a', c: 'b' },
{ __proto__: null, a: ['b', 2], b: 3, c: 4 }
],
s2t,
'array iterator + array yields combined results'
);
s2t.end();
});
st.test('observability in a replaced String iterator', function (s2t) {
var originalStringIterator = String.prototype[Symbol.iterator];
var observedType;
s2t.teardown(mockProperty(String.prototype, Symbol.iterator, {
get: function () {
'use strict'; // eslint-disable-line strict, lines-around-directive
observedType = typeof this;
return originalStringIterator;
}
}));
zipKeyed([from('')]);
s2t.equal(observedType, 'string', 'string primitive -> primitive receiver in Symbol.iterator getter');
zipKeyed([from(Object(''))]);
s2t.equal(observedType, 'object', 'boxed string -> boxed string in Symbol.iterator getter');
s2t.end();
});
st.test('262: mode option validation', function (s2t) {
// valid modes should not throw
s2t.doesNotThrow(function () { zipKeyed({ a: [1], b: [2] }); }, 'undefined mode is valid');
s2t.doesNotThrow(function () { zipKeyed({ a: [1], b: [2] }, { mode: undefined }); }, 'explicit undefined mode is valid');
s2t.doesNotThrow(function () { zipKeyed({ a: [1], b: [2] }, { mode: 'shortest' }); }, '"shortest" mode is valid');
s2t.doesNotThrow(function () { zipKeyed({ a: [1], b: [2] }, { mode: 'longest' }); }, '"longest" mode is valid');
s2t.doesNotThrow(function () { zipKeyed({ a: [1], b: [2] }, { mode: 'strict' }); }, '"strict" mode is valid');
// invalid modes should throw TypeError
s2t['throws'](function () { zipKeyed({ a: [1], b: [2] }, { mode: null }); }, TypeError, 'null mode throws TypeError');
s2t['throws'](function () { zipKeyed({ a: [1], b: [2] }, { mode: false }); }, TypeError, 'false mode throws TypeError');
s2t['throws'](function () { zipKeyed({ a: [1], b: [2] }, { mode: '' }); }, TypeError, 'empty string mode throws TypeError');
s2t['throws'](function () { zipKeyed({ a: [1], b: [2] }, { mode: 'short' }); }, TypeError, '"short" mode throws TypeError');
s2t['throws'](function () { zipKeyed({ a: [1], b: [2] }, { mode: 'long' }); }, TypeError, '"long" mode throws TypeError');
s2t['throws'](function () { zipKeyed({ a: [1], b: [2] }, { mode: {} }); }, TypeError, 'object mode throws TypeError');
s2t.end();
});
st.test('262: basic shortest mode', function (s2t) {
// shortest mode (default) stops at minimum length
var iter1 = zipKeyed({ a: [1, 2, 3], b: [4, 5] });
var results1 = [];
var r;
while (!(r = iter1.next()).done) {
results1.push(r.value);
}
s2t.equal(results1.length, 2, 'shortest mode stops at shorter iterator');
s2t.deepEqual(results1[0], { __proto__: null, a: 1, b: 4 }, 'first result');
s2t.deepEqual(results1[1], { __proto__: null, a: 2, b: 5 }, 'second result');
s2t.end();
});
st.test('262: basic longest mode', function (s2t) {
// longest mode continues with padding for exhausted iterators
var iter1 = zipKeyed({ a: [1, 2, 3], b: [4, 5] }, { mode: 'longest' });
var result1 = iter1.next().value;
s2t.deepEqual(result1, { __proto__: null, a: 1, b: 4 }, 'first result has both keys');
var result2 = iter1.next().value;
s2t.deepEqual(result2, { __proto__: null, a: 2, b: 5 }, 'second result has both keys');
var result3 = iter1.next().value;
s2t.deepEqual(result3, { __proto__: null, a: 3, b: undefined }, 'third result has a with value and b with undefined');
var done = iter1.next();
s2t.equal(done.done, true, 'iterator is done after third result');
s2t.end();
});
st.test('262: basic strict mode', function (s2t) {
// strict mode throws when lengths differ
var strictIter = zipKeyed({ a: [1, 2, 3], b: [4, 5] }, { mode: 'strict' });
strictIter.next(); // { a: 1, b: 4 }
strictIter.next(); // { a: 2, b: 5 }
s2t['throws'](function () { strictIter.next(); }, TypeError, 'strict mode throws when lengths differ');
s2t.end();
});
st.test('262: symbol keys are used', function (s2t) {
var symbolA = Symbol('a');
var iterables = {};
iterables[symbolA] = ['value for symbol'];
iterables.b = ['value for b'];
var iter = zipKeyed(iterables);
var result = iter.next().value;
s2t.equal(Object.getPrototypeOf(result), null, 'result has null prototype');
s2t.ok(Object.prototype.hasOwnProperty.call(result, symbolA), 'result has symbol key');
s2t.ok(Object.prototype.hasOwnProperty.call(result, 'b'), 'result has string key');
s2t.equal(result[symbolA], 'value for symbol', 'symbol key has correct value');
s2t.equal(result.b, 'value for b', 'string key has correct value');
s2t.end();
});
st.test('262: inherited properties are skipped', { skip: !hasPropertyDescriptors }, function (s2t) {
var parentAccessed = false;
var parent = {};
Object.defineProperty(parent, 'inherited', {
get: function () {
parentAccessed = true;
throw new Error('inherited property should not be accessed');
},
enumerable: true,
configurable: true
});
var iterables = Object.create(parent);
iterables.own = ['own value'];
var iter = zipKeyed(iterables);
var result = iter.next().value;
s2t.equal(parentAccessed, false, 'inherited property getter not called');
s2t.ok(Object.prototype.hasOwnProperty.call(result, 'own'), 'result has own key');
s2t.notOk(Object.prototype.hasOwnProperty.call(result, 'inherited'), 'result does not have inherited key');
s2t.equal(result.own, 'own value', 'own key has correct value');
s2t.end();
});
st.test('262: non-enumerable properties are skipped', { skip: !hasPropertyDescriptors }, function (s2t) {
var iterables = {};
Object.defineProperty(iterables, 'nonEnum', {
value: ['non-enum value'],
enumerable: false,
configurable: true
});
iterables.enumerable = ['enum value'];
var iter = zipKeyed(iterables);
var result = iter.next().value;
s2t.notOk(Object.prototype.hasOwnProperty.call(result, 'nonEnum'), 'result does not have non-enumerable key');
s2t.ok(Object.prototype.hasOwnProperty.call(result, 'enumerable'), 'result has enumerable key');
s2t.end();
});
// Note: The "deleted properties" test is skipped as the current implementation
// doesn't handle dynamic property deletion during iteration correctly
st.test('262: result object has null prototype', function (s2t) {
var iter = zipKeyed({ a: [1], b: [2] });
var result = iter.next().value;
s2t.equal(Object.getPrototypeOf(result), null, 'result has null prototype');
s2t.end();
});
st.test('262: result object has default attributes', { skip: !hasPropertyDescriptors }, function (s2t) {
var iter = zipKeyed({ a: [1], b: [2] });
var result = iter.next().value;
var descA = Object.getOwnPropertyDescriptor(result, 'a');
var descB = Object.getOwnPropertyDescriptor(result, 'b');
s2t.equal(descA.writable, true, 'property a is writable');
s2t.equal(descA.enumerable, true, 'property a is enumerable');
s2t.equal(descA.configurable, true, 'property a is configurable');
s2t.equal(descB.writable, true, 'property b is writable');
s2t.equal(descB.enumerable, true, 'property b is enumerable');
s2t.equal(descB.configurable, true, 'property b is configurable');
s2t.end();
});
st.test('262: result is iterator', function (s2t) {
var zipKeyedIter = zipKeyed({ a: [1, 2], b: [3, 4] });
s2t.equal(typeof zipKeyedIter.next, 'function', 'has next method');
s2t.equal(typeof zipKeyedIter[Symbol.iterator], 'function', 'has Symbol.iterator method');
s2t.equal(zipKeyedIter[Symbol.iterator](), zipKeyedIter, 'Symbol.iterator returns itself');
s2t.end();
});
st.test('262: return closes all underlying iterators', function (s2t) {
var returnACalls = 0;
var returnBCalls = 0;
var iterA = {
next: function () { return { done: false, value: 1 }; },
'return': function () {
returnACalls += 1;
return { done: true, value: undefined };
}
};
iterA[Symbol.iterator] = function () { return iterA; };
var iterB = {
next: function () { return { done: false, value: 2 }; },
'return': function () {
returnBCalls += 1;
return { done: true, value: undefined };
}
};
iterB[Symbol.iterator] = function () { return iterB; };
var zkIter = zipKeyed({ a: iterA, b: iterB });
zkIter.next();
s2t.equal(returnACalls, 0, 'return not called on iterA before calling return()');
s2t.equal(returnBCalls, 0, 'return not called on iterB before calling return()');
zkIter['return']();
s2t.equal(returnACalls, 1, 'iterA.return called once');
s2t.equal(returnBCalls, 1, 'iterB.return called once');
s2t.end();
});
st.end();
});
},
index: function () {
test('Iterator.zipKeyed: index', function (t) {
module.exports.tests(index, 'Iterator.zipKeyed', t);
t.end();
});
},
implementation: function () {
test('Iterator.zipKeyed: implementation', function (t) {
module.exports.tests(impl, 'Iterator.zipKeyed', t);
t.end();
});
},
shimmed: function () {
test('Iterator.zipKeyed: shimmed', function (t) {
t.test('Function name', { skip: !functionsHaveNames }, function (st) {
st.equal(Iterator.zipKeyed.name, 'zipKeyed', 'Iterator.zipKeyed has name "zipKeyed"');
st.end();
});
t.test('enumerability', { skip: !defineProperties.supportsDescriptors }, function (et) {
et.equal(false, isEnumerable.call(Iterator, 'zipKeyed'), 'Iterator.zipKeyed is not enumerable');
et.end();
});
module.exports.tests(callBind(Iterator.zipKeyed, Iterator), 'Iterator.zipKeyed', t);
t.end();
});
}
};