es-iterator-helpers
Version:
An ESnext spec-compliant iterator helpers shim/polyfill/replacement that works as far down as ES3.
287 lines (249 loc) • 9.05 kB
JavaScript
;
var defineProperties = require('define-properties');
var test = require('tape');
var callBind = require('call-bind');
var functionsHaveNames = require('functions-have-names')();
var hasStrictMode = require('has-strict-mode')();
var forEach = require('for-each');
var debug = require('object-inspect');
var v = require('es-value-fixtures');
var hasSymbols = require('has-symbols/shams')();
var iterate = require('iterate-iterator');
var index = require('../Iterator.prototype.some');
var impl = require('../Iterator.prototype.some/implementation');
var fnName = 'some';
var isEnumerable = Object.prototype.propertyIsEnumerable;
var testIterator = require('./helpers/testIterator');
module.exports = {
tests: function (some, name, t) {
t['throws'](
function () { return new some(); }, // eslint-disable-line new-cap
TypeError,
'`' + name + '` is not a constructor'
);
forEach(v.primitives.concat(v.objects), function (nonIterator) {
t['throws'](
function () { iterate(some(nonIterator, function () {})); },
TypeError,
debug(nonIterator) + ' is not an Object with a callable `next` method'
);
var badNext = { next: nonIterator };
t['throws'](
function () { iterate(some(badNext, function () {})); },
TypeError,
debug(badNext) + ' is not an Object with a callable `next` method'
);
});
forEach(v.nonFunctions, function (nonFunction) {
t['throws'](
function () { some({ next: function () {} }, nonFunction); },
TypeError,
debug(nonFunction) + ' is not a function'
);
});
t.test('actual iteration', { skip: !hasSymbols }, function (st) {
var arr = [1, 2, 3];
var iterator = callBind(arr[Symbol.iterator], arr);
st['throws'](
function () { return new some(iterator()); }, // eslint-disable-line new-cap
TypeError,
'`' + name + '` iterator is not a constructor'
);
st['throws'](
function () { return new some(iterator(), function () {}); }, // eslint-disable-line new-cap
TypeError,
'`' + name + '` iterator is not a constructor'
);
testIterator(iterator(), [1, 2, 3], st, 'original');
st.equal(some(iterator(), function () { return false; }), false, 'some for always-false');
st.equal(some(iterator(), function () { return true; }), true, 'some for always-true');
st.equal(some(iterator(), function (x, i) { return x === 2 && i === 1; }), true, 'some returns true for matching value/index');
st.test('test262: test/built-ins/Iterator/prototype/some/predicate-args', function (s2t) {
var assertionCount = 0;
var result = some(
['a', 'b', 'c'][Symbol.iterator](),
function (value, count) {
if (value === 'a') {
s2t.equal(count, 0);
} else if (value === 'b') {
s2t.equal(count, 1);
} else if (value === 'c') {
s2t.equal(count, 2);
} else {
s2t.fail('unexpected value');
}
assertionCount += 1;
return false;
}
);
s2t.equal(result, false, 'some returns false when none match');
s2t.equal(assertionCount, 3, 'predicate called three times');
s2t.end();
});
st.test('test262: test/built-ins/Iterator/prototype/some/predicate-this', function (s2t) {
var expectedThis = (function () { return this; }()); // eslint-disable-line no-invalid-this
var assertionCount = 0;
var result = some(
[0][Symbol.iterator](),
function () {
s2t.equal(this, expectedThis, 'predicate this is undefined'); // eslint-disable-line no-invalid-this
assertionCount += 1;
return true;
}
);
s2t.equal(result, true);
s2t.equal(assertionCount, 1);
s2t.end();
});
st.test('test262: test/built-ins/Iterator/prototype/some/predicate-returns-truthy', function (s2t) {
var callCount = 0;
var returnCalled = false;
var values = [0, 1, 2];
var idx = 0;
var iter = {
next: function () {
if (idx < values.length) {
var val = values[idx];
idx += 1;
return { done: false, value: val };
}
return { done: true, value: undefined };
},
'return': function () {
returnCalled = true;
return { done: true, value: undefined };
}
};
var result = some(
iter,
function () {
callCount += 1;
return true;
}
);
s2t.equal(result, true, 'some returns true when predicate returns truthy');
s2t.equal(callCount, 1, 'predicate called once');
s2t.equal(returnCalled, true, 'iterator is closed');
s2t.end();
});
st.test('test262: test/built-ins/Iterator/prototype/some/predicate-returns-falsey', function (s2t) {
var result = some(
[0, 1, 2, 3, 4][Symbol.iterator](),
function () { return false; }
);
s2t.equal(result, false, 'some returns false when predicate always returns falsey');
s2t.end();
});
st.test('test262: test/built-ins/Iterator/prototype/some/predicate-returns-falsey-then-truthy', function (s2t) {
var callCount = 0;
var returnCalled = false;
var values = [0, 1, 2, 3, 4];
var idx = 0;
var iter = {
next: function () {
if (idx < values.length) {
var val = values[idx];
idx += 1;
return { done: false, value: val };
}
return { done: true, value: undefined };
},
'return': function () {
returnCalled = true;
return { done: true, value: undefined };
}
};
var result = some(
iter,
function (value) {
callCount += 1;
return value >= 3;
}
);
s2t.equal(result, true, 'some returns true when predicate returns truthy');
s2t.equal(callCount, 4, 'predicate called until truthy returned');
s2t.equal(returnCalled, true, 'iterator is closed');
s2t.end();
});
st.test('test262: test/built-ins/Iterator/prototype/some/predicate-returns-non-boolean', function (s2t) {
// truthy non-boolean values
s2t.equal(some([1][Symbol.iterator](), function () { return 1; }), true, 'truthy number');
s2t.equal(some([1][Symbol.iterator](), function () { return 'yes'; }), true, 'truthy string');
s2t.equal(some([1][Symbol.iterator](), function () { return {}; }), true, 'truthy object');
// falsy non-boolean values
s2t.equal(some([1][Symbol.iterator](), function () { return 0; }), false, 'falsy number');
s2t.equal(some([1][Symbol.iterator](), function () { return ''; }), false, 'falsy string');
s2t.equal(some([1][Symbol.iterator](), function () { return null; }), false, 'null');
s2t.end();
});
st.test('test262: test/built-ins/Iterator/prototype/some/predicate-throws', function (s2t) {
var returnCount = 0;
var testIter = {
next: function () {
return { done: false, value: 1 };
},
'return': function () {
returnCount += 1;
return { done: true };
}
};
var callbackCount = 0;
s2t['throws'](
function () {
some(testIter, function () {
callbackCount += 1;
throw new SyntaxError('predicate threw');
});
},
SyntaxError
);
s2t.equal(callbackCount, 1, 'predicate called once');
s2t.equal(returnCount, 1, 'iterator closed when predicate throws');
s2t.end();
});
st.test('test262: test/built-ins/Iterator/prototype/some/iterator-already-exhausted', function (s2t) {
var iter = [][Symbol.iterator]();
var callbackCount = 0;
var result = some(iter, function () {
callbackCount += 1;
return true;
});
s2t.equal(result, false, 'some returns false for empty iterator');
s2t.equal(callbackCount, 0, 'predicate not called');
s2t.end();
});
st.end();
});
},
index: function () {
test('Iterator.prototype.' + fnName + ': index', function (t) {
module.exports.tests(index, 'Iterator.prototype.' + fnName, t);
t.end();
});
},
implementation: function () {
test('Iterator.prototype.' + fnName + ': implementation', function (t) {
module.exports.tests(callBind(impl), 'Iterator.prototype.' + fnName, t);
t.end();
});
},
shimmed: function () {
test('Iterator.prototype.' + fnName + ': shimmed', function (t) {
t.test('Function name', { skip: !functionsHaveNames }, function (st) {
st.equal(Iterator.prototype[fnName].name, fnName, 'Iterator#' + fnName + ' has name "' + fnName + '"');
st.end();
});
t.test('enumerability', { skip: !defineProperties.supportsDescriptors }, function (et) {
et.equal(false, isEnumerable.call(Iterator.prototype, fnName), 'Iterator#' + fnName + ' is not enumerable');
et.end();
});
t.test('bad string/this value', { skip: !hasStrictMode }, function (st) {
st['throws'](function () { return Iterator.prototype[fnName].call(undefined, 'a'); }, TypeError, 'undefined is not an object');
st['throws'](function () { return Iterator.prototype[fnName].call(null, 'a'); }, TypeError, 'null is not an object');
st.end();
});
module.exports.tests(callBind(Iterator.prototype[fnName]), 'Iterator.prototype.' + fnName, t);
t.end();
});
}
};