es-iterator-helpers
Version:
An ESnext spec-compliant iterator helpers shim/polyfill/replacement that works as far down as ES3.
279 lines (227 loc) • 11.3 kB
JavaScript
'use strict';
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 mockProperty = require('mock-property');
var index = require('../Iterator.zip');
var impl = require('../Iterator.zip/implementation');
var from = require('../Iterator.from/polyfill')();
var isEnumerable = Object.prototype.propertyIsEnumerable;
var testIterator = require('./helpers/testIterator');
module.exports = {
tests: function (zip, name, t) {
t['throws'](
function () { return new zip(); }, // eslint-disable-line new-cap
TypeError,
'`' + name + '` itself is not a constructor'
);
t['throws'](
function () { return new zip({}); }, // eslint-disable-line new-cap
TypeError,
'`' + name + '` itself is not a constructor, with an argument'
);
forEach(v.primitives.concat(v.objects), function (nonIterator) {
t['throws'](
function () { zip(nonIterator, []); },
TypeError,
debug(nonIterator) + ' 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 () { zip([[], badIterable, []]).next(); },
TypeError,
debug(badIterable) + ' is not a function'
);
}
});
forEach(v.strings, function (string) {
st['throws'](
function () { zip([string]); },
TypeError,
'non-objects are not considered iterable'
);
});
var arrayIt = zip([[1, 2, 3]]);
st.equal(typeof arrayIt.next, 'function', 'has a `next` function');
st.test('real iterators', { skip: !hasSymbols }, function (s2t) {
var iter = [1, 2][Symbol.iterator]();
testIterator(zip([iter, [3, 4]]), [[1, 3], [2, 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;
}
}));
zip([from('')]);
s2t.equal(observedType, 'string', 'string primitive -> primitive receiver in Symbol.iterator getter');
zip([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 () { zip([[1], [2]]); }, 'undefined mode is valid');
s2t.doesNotThrow(function () { zip([[1], [2]], { mode: undefined }); }, 'explicit undefined mode is valid');
s2t.doesNotThrow(function () { zip([[1], [2]], { mode: 'shortest' }); }, '"shortest" mode is valid');
s2t.doesNotThrow(function () { zip([[1], [2]], { mode: 'longest' }); }, '"longest" mode is valid');
s2t.doesNotThrow(function () { zip([[1], [2]], { mode: 'strict' }); }, '"strict" mode is valid');
// invalid modes should throw TypeError
s2t['throws'](function () { zip([[1], [2]], { mode: null }); }, TypeError, 'null mode throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: false }); }, TypeError, 'false mode throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: '' }); }, TypeError, 'empty string mode throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: 'short' }); }, TypeError, '"short" mode throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: 'long' }); }, TypeError, '"long" mode throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: 'loose' }); }, TypeError, '"loose" mode throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: 0 }); }, TypeError, '0 mode throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: {} }); }, TypeError, 'object mode throws TypeError');
// String wrapper should not be coerced
s2t['throws'](function () { zip([[1], [2]], { mode: Object('shortest') }); }, TypeError, 'String wrapper mode throws TypeError');
// objects with toString/valueOf should not be coerced
s2t['throws'](function () { zip([[1], [2]], { mode: { toString: function () { return 'shortest'; } } }); }, TypeError, 'object with toString throws TypeError');
s2t['throws'](function () { zip([[1], [2]], { mode: { valueOf: function () { return 'shortest'; } } }); }, TypeError, 'object with valueOf throws TypeError');
s2t.end();
});
st.test('262: basic shortest mode', function (s2t) {
// shortest mode (default) stops at minimum length
testIterator(zip([[1, 2, 3], [4, 5]]), [[1, 4], [2, 5]], s2t, 'shortest mode stops at shorter iterator');
testIterator(zip([[1, 2], [3, 4, 5]]), [[1, 3], [2, 4]], s2t, 'shortest mode stops at shorter first iterator');
testIterator(zip([[1], [2], [3]]), [[1, 2, 3]], s2t, 'three iterators of length 1');
testIterator(zip([[], [1, 2, 3]]), [], s2t, 'empty first iterator yields nothing');
testIterator(zip([[1, 2, 3], []]), [], s2t, 'empty second iterator yields nothing');
// explicit shortest mode
testIterator(zip([[1, 2, 3], [4, 5]], { mode: 'shortest' }), [[1, 4], [2, 5]], s2t, 'explicit shortest mode');
s2t.end();
});
st.test('262: basic longest mode', function (s2t) {
// longest mode continues with undefined padding by default
testIterator(zip([[1, 2, 3], [4, 5]], { mode: 'longest' }), [[1, 4], [2, 5], [3, undefined]], s2t, 'longest mode pads with undefined');
testIterator(zip([[1, 2], [3, 4, 5]], { mode: 'longest' }), [[1, 3], [2, 4], [undefined, 5]], s2t, 'longest mode pads first iterator');
testIterator(zip([[1], [2, 3], [4, 5, 6]], { mode: 'longest' }), [[1, 2, 4], [undefined, 3, 5], [undefined, undefined, 6]], s2t, 'longest mode with three iterators');
s2t.end();
});
st.test('262: basic strict mode', function (s2t) {
// strict mode succeeds when lengths match
testIterator(zip([[1, 2], [3, 4]], { mode: 'strict' }), [[1, 3], [2, 4]], s2t, 'strict mode succeeds with equal lengths');
testIterator(zip([[1], [2], [3]], { mode: 'strict' }), [[1, 2, 3]], s2t, 'strict mode with three iterators of length 1');
// strict mode throws when lengths differ
var strictIter1 = zip([[1, 2, 3], [4, 5]], { mode: 'strict' });
strictIter1.next(); // [1, 4]
strictIter1.next(); // [2, 5]
s2t['throws'](function () { strictIter1.next(); }, TypeError, 'strict mode throws when first iterator has more');
var strictIter2 = zip([[1, 2], [3, 4, 5]], { mode: 'strict' });
strictIter2.next(); // [1, 3]
strictIter2.next(); // [2, 4]
s2t['throws'](function () { strictIter2.next(); }, TypeError, 'strict mode throws when second iterator has more');
s2t.end();
});
st.test('262: padding option validation', function (s2t) {
// padding is only used in longest mode
s2t.doesNotThrow(function () { zip([[1], [2]], { mode: 'shortest', padding: null }); }, 'invalid padding ignored in shortest mode');
s2t.doesNotThrow(function () { zip([[1], [2]], { mode: 'strict', padding: null }); }, 'invalid padding ignored in strict mode');
// invalid padding in longest mode
s2t['throws'](function () { zip([[1], [2]], { mode: 'longest', padding: null }); }, TypeError, 'null padding throws in longest mode');
s2t['throws'](function () { zip([[1], [2]], { mode: 'longest', padding: 'abc' }); }, TypeError, 'string padding throws in longest mode');
s2t['throws'](function () { zip([[1], [2]], { mode: 'longest', padding: 123 }); }, TypeError, 'number padding throws in longest mode');
s2t['throws'](function () { zip([[1], [2]], { mode: 'longest', padding: true }); }, TypeError, 'boolean padding throws in longest mode');
s2t.end();
});
st.test('262: result is iterator', function (s2t) {
var zipIter = zip([[1, 2], [3, 4]]);
s2t.equal(typeof zipIter.next, 'function', 'has next method');
s2t.equal(typeof zipIter[Symbol.iterator], 'function', 'has Symbol.iterator method');
s2t.equal(zipIter[Symbol.iterator](), zipIter, 'Symbol.iterator returns itself');
s2t.end();
});
st.test('262: return closes all underlying iterators', function (s2t) {
var return1Calls = 0;
var return2Calls = 0;
var iter1 = {
next: function () { return { done: false, value: 1 }; },
'return': function () {
return1Calls += 1;
return { done: true, value: undefined };
}
};
iter1[Symbol.iterator] = function () { return iter1; };
var iter2 = {
next: function () { return { done: false, value: 2 }; },
'return': function () {
return2Calls += 1;
return { done: true, value: undefined };
}
};
iter2[Symbol.iterator] = function () { return iter2; };
var zipIter = zip([iter1, iter2]);
zipIter.next();
s2t.equal(return1Calls, 0, 'return not called before calling return()');
s2t.equal(return2Calls, 0, 'return not called before calling return()');
zipIter['return']();
s2t.equal(return1Calls, 1, 'iter1.return called once');
s2t.equal(return2Calls, 1, 'iter2.return called once');
s2t.end();
});
st.test('262: next method throws closes other iterators', function (s2t) {
var return2Calls = 0;
var iter1 = {
next: function () { throw new EvalError('iter1 next threw'); }
};
iter1[Symbol.iterator] = function () { return iter1; };
var iter2 = {
next: function () { return { done: false, value: 2 }; },
'return': function () {
return2Calls += 1;
return { done: true, value: undefined };
}
};
iter2[Symbol.iterator] = function () { return iter2; };
var zipIter = zip([iter1, iter2]);
s2t['throws'](function () { zipIter.next(); }, EvalError, 'throws error from iter1.next');
s2t.equal(return2Calls, 1, 'iter2.return called when iter1.next throws');
s2t.end();
});
st.end();
});
},
index: function () {
test('Iterator.zip: index', function (t) {
module.exports.tests(index, 'Iterator.zip', t);
t.end();
});
},
implementation: function () {
test('Iterator.zip: implementation', function (t) {
module.exports.tests(impl, 'Iterator.zip', t);
t.end();
});
},
shimmed: function () {
test('Iterator.zip: shimmed', function (t) {
t.test('Function name', { skip: !functionsHaveNames }, function (st) {
st.equal(Iterator.zip.name, 'zip', 'Iterator.zip has name "zip"');
st.end();
});
t.test('enumerability', { skip: !defineProperties.supportsDescriptors }, function (et) {
et.equal(false, isEnumerable.call(Iterator, 'zip'), 'Iterator.zip is not enumerable');
et.end();
});
module.exports.tests(callBind(Iterator.zip, Iterator), 'Iterator.zip', t);
t.end();
});
}
};