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Only bind listeners when necessary

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This commit is contained in:
ahocevar
2019-08-29 22:35:32 +02:00
parent aca4a39863
commit fe83d1b32c
2 changed files with 25 additions and 20 deletions
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21
src/ol/events.js
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@@ -32,14 +32,19 @@ import {clear} from './obj.js';
* @return {ListenerFunction} Bound listener.
*/
export function bindListener(listenerObj) {
const boundListener = function(evt) {
const listener = listenerObj.listener;
const bindTo = listenerObj.bindTo || listenerObj.target;
if (listenerObj.callOnce) {
unlistenByKey(listenerObj);
}
return listener.call(bindTo, evt);
};
let boundListener;
if (listenerObj.bindTo || listenerObj.callOnce) {
boundListener = function(evt) {
const listener = listenerObj.listener;
const bindTo = listenerObj.bindTo || listenerObj.target;
if (listenerObj.callOnce) {
unlistenByKey(listenerObj);
}
return listener.call(bindTo, evt);
};
} else {
boundListener = listenerObj.listener;
}
listenerObj.boundListener = boundListener;
return boundListener;
}

24
test/spec/ol/events.test.js
View File

@@ -24,15 +24,14 @@ describe('ol.events', function() {
boundListener();
expect(listenerObj.listener.thisValues[0]).to.equal(listenerObj.bindTo);
});
it('binds to the target when bindTo is not provided', function() {
const listenerObj = {
listener: sinon.spy(),
target: {id: 1}
};
const boundListener = bindListener(listenerObj);
expect(listenerObj.boundListener).to.equal(boundListener);
boundListener();
expect(listenerObj.listener.thisValues[0]).to.equal(listenerObj.target);
it('binds to the target when bindTo is not provided', function(done) {
const target = new EventTarget();
const listenerObj = listen(target, 'foo', function() {
expect(this).to.equal(target);
done();
});
expect(listenerObj.boundListener).to.equal(listenerObj.listener);
target.dispatchEvent('foo');
});
it('binds a self-unregistering listener when callOnce is true', function() {
const bindTo = {id: 1};
@@ -122,13 +121,14 @@ describe('ol.events', function() {
describe('listenOnce()', function() {
it('creates a one-off listener', function() {
const target = new EventTarget();
const listener = sinon.spy();
const key = listenOnce(target, 'foo', listener);
expect(add.callCount).to.be(1);
expect(key.callOnce).to.be(true);
key.boundListener();
target.dispatchEvent('foo');
expect(listener.callCount).to.be(1);
target.dispatchEvent('foo');
expect(listener.callCount).to.be(1);
expect(remove.callCount).to.be(1);
});
it('does not add the same listener twice', function() {
const listener = function() {};