gristlabs_grist-core/test/client/lib/koUtil.js

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/* global describe, it */
var assert = require('assert');
var ko = require('knockout');
var sinon = require('sinon');
var koUtil = require('app/client/lib/koUtil');
describe('koUtil', function() {
describe("observableWithDefault", function() {
it("should be an observable with a default", function() {
var foo = ko.observable();
var bar1 = koUtil.observableWithDefault(foo, 'defaultValue');
var obj = { prop: 17 };
var bar2 = koUtil.observableWithDefault(foo, function() { return this.prop; }, obj);
assert.equal(bar1(), 'defaultValue');
assert.equal(bar2(), 17);
foo('hello');
assert.equal(bar1(), 'hello');
assert.equal(bar2(), 'hello');
obj.prop = 28;
foo(0);
assert.equal(bar1(), 'defaultValue');
assert.equal(bar2(), 28);
bar1('world');
assert.equal(foo(), 'world');
assert.equal(bar1(), 'world');
assert.equal(bar2(), 'world');
bar2('blah');
assert.equal(foo(), 'blah');
assert.equal(bar1(), 'blah');
assert.equal(bar2(), 'blah');
bar1(null);
assert.equal(foo(), null);
assert.equal(bar1(), 'defaultValue');
assert.equal(bar2(), 28);
});
});
describe('computedAutoDispose', function() {
function testAutoDisposeValue(pure) {
var obj = [{dispose: sinon.spy()}, {dispose: sinon.spy()}, {dispose: sinon.spy()}];
var which = ko.observable(0);
var computedBody = sinon.spy(function() { return obj[which()]; });
var foo = koUtil.computedAutoDispose({ read: computedBody, pure: pure });
// An important difference between pure and not is whether it is immediately evaluated.
assert.equal(computedBody.callCount, pure ? 0 : 1);
assert.strictEqual(foo(), obj[0]);
assert.equal(computedBody.callCount, 1);
which(1);
assert.strictEqual(foo(), obj[1]);
assert.equal(computedBody.callCount, 2);
assert.equal(obj[0].dispose.callCount, 1);
assert.equal(obj[1].dispose.callCount, 0);
// Another difference is whether changes cause immediate re-evaluation.
which(2);
assert.equal(computedBody.callCount, pure ? 2 : 3);
assert.equal(obj[1].dispose.callCount, pure ? 0 : 1);
foo.dispose();
assert.equal(obj[0].dispose.callCount, 1);
assert.equal(obj[1].dispose.callCount, 1);
assert.equal(obj[2].dispose.callCount, pure ? 0 : 1);
}
it("autoDisposeValue for pure computed should be pure", function() {
testAutoDisposeValue(true);
});
it("autoDisposeValue for non-pure computed should be non-pure", function() {
testAutoDisposeValue(false);
});
});
describe('computedBuilder', function() {
it("should create appropriate dependencies and dispose values", function() {
var index = ko.observable(0);
var foo = ko.observable('foo'); // used in the builder's constructor
var faz = ko.observable('faz'); // used in the builder's dispose
var obj = [{dispose: sinon.spy(() => faz())}, {dispose: sinon.spy(() => faz())}];
var builder = sinon.spy(function(i) { obj[i].foo = foo(); return obj[i]; });
// The built observable should depend on index(), should NOT depend on foo() or faz(), and
// returned values should get disposed.
var built = koUtil.computedBuilder(function() { return builder.bind(null, index()); });
assert.equal(builder.callCount, 1);
assert.strictEqual(built(), obj[0]);
assert.equal(built().foo, 'foo');
foo('bar');
assert.equal(builder.callCount, 1);
faz('baz');
assert.equal(builder.callCount, 1);
// Changing index should dispose the previous value and rebuild.
index(1);
assert.equal(obj[0].dispose.callCount, 1);
assert.equal(builder.callCount, 2);
assert.strictEqual(built(), obj[1]);
assert.equal(built().foo, 'bar');
// Changing foo() or faz() should continue to have no effect (i.e. disposing the previous
// value should not have created any dependencies.)
foo('foo');
assert.equal(builder.callCount, 2);
faz('faz');
assert.equal(builder.callCount, 2);
// Disposing the built observable should dispose the last returned value.
assert.equal(obj[1].dispose.callCount, 0);
built.dispose();
assert.equal(obj[1].dispose.callCount, 1);
});
});
});