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fix(scopes): correctly meassure perf impact of one-time expressions #124

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fix(scopes): correctly meassure perf impact of one-time expressions #124

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db2c017
fix(scopes): correctly meassure perf impact of one-time expressions
gkalpak Mar 30, 2017
8a5f7c4
fixup! fix(scopes): correctly meassure perf impact of one-time expres…
gkalpak Mar 30, 2017
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103 changes: 37 additions & 66 deletions src/modules/scopes.js
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Original file line number Diff line number Diff line change
Expand Up @@ -79,37 +79,20 @@ function decorateRootScope($delegate, $parse) {
var _digestEvents = [];
var skipNextPerfWatchers = false;
scopePrototype.$watch = function (watchExpression, reactionFunction) {
// if `skipNextPerfWatchers` is true, this means the previous run of the
// `$watch` decorator was a one time binding expression and this invocation
// of the $watch function has the `oneTimeInterceptedExpression` (internal angular function)
// as the `watchExpression` parameter. If we decorate it with the performance
// timers function this will cause us to invoke `oneTimeInterceptedExpression`
// on subsequent digest loops and will update the one time bindings
// if anything mutated the property.
if (skipNextPerfWatchers) {
skipNextPerfWatchers = false;
return _watch.apply(this, arguments);
}

if (typeof watchExpression === 'string' &&
isOneTimeBindExp(watchExpression)) {
skipNextPerfWatchers = true;
return _watch.apply(this, arguments);
}
var watchStr = humanReadableWatchExpression(watchExpression);
var scopeId = this.$id;
var expressions = null;
if (typeof watchExpression === 'function') {
expressions = watchExpression.expressions;
if (Object.prototype.toString.call(expressions) === '[object Array]' &&
expressions.some(isOneTimeBindExp)) {
skipNextPerfWatchers = true;
return _watch.apply(this, arguments);
}

arguments[0] = function () {
// Convert the `watchExpression` to a function (if not already one).
// This is also the first thing `Scope.$watch()` does.
var parsedExpression = $parse(watchExpression);

// Only intercept this call if there is no `$$watchDelegate`.
// (With `$$watchDelegate` there will be subsequent calls to `$watch` (if necessary)).
if (!parsedExpression.$$watchDelegate) {
var scopeId = this.$id;
var watchStr = humanReadableWatchExpression(watchExpression);

// Intercept the `watchExpression` (if any).
arguments[0] = simpleExtend(function() {
var start = perf.now();
var ret = watchExpression.apply(this, arguments);
var ret = parsedExpression.apply(this, arguments);
var end = perf.now();
_digestEvents.push({
eventType: 'scope:watch',
Expand All @@ -118,36 +101,23 @@ function decorateRootScope($delegate, $parse) {
time: end - start
});
return ret;
};
} else {
var thatScope = this;
arguments[0] = function () {
var start = perf.now();
var ret = thatScope.$eval(watchExpression);
var end = perf.now();
_digestEvents.push({
eventType: 'scope:watch',
id: scopeId,
watch: watchStr,
time: end - start
});
return ret;
};
}

if (typeof reactionFunction === 'function') {
arguments[1] = function () {
var start = perf.now();
var ret = reactionFunction.apply(this, arguments);
var end = perf.now();
_digestEvents.push({
eventType: 'scope:reaction',
id: scopeId,
watch: watchStr,
time: end - start
});
return ret;
};
}, parsedExpression);

// Intercept the `reactionFunction` (if any).
if (typeof reactionFunction === 'function') {
arguments[1] = function() {
var start = perf.now();
var ret = reactionFunction.apply(this, arguments);
var end = perf.now();
_digestEvents.push({
eventType: 'scope:reaction',
id: scopeId,
watch: watchStr,
time: end - start
});
return ret;
};
}
}

return _watch.apply(this, arguments);
Expand Down Expand Up @@ -355,12 +325,13 @@ function humanReadableWatchExpression (fn) {
return fn.toString();
}

function isOneTimeBindExp(exp) {
// this is the same code angular 1.3.15 has to check
// for a one time bind expression
return exp.charAt(0) === ':' && exp.charAt(1) === ':';
}

function convertIdToOriginalType(scopeId) {
return (angular.version.minor < 3) ? scopeId : parseInt(scopeId, 10);
}

function simpleExtend(dst, src) {
Object.keys(src).forEach(function(key) {
dst[key] = src[key];
});
return dst;
}
141 changes: 114 additions & 27 deletions test/scopes.spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -72,33 +72,120 @@ describe('ngHintScopes', function() {
});

if (angular.version.minor >= 3) {
it('should not run perf timers for one time bind expressions passed to watch', function() {
var calls = hint.emit.calls;
scope.$watch('::a.b', function() {});
expect(calls.count()).toBe(0);

scope.$apply();
var evt = calls.mostRecent().args[1].events[0];
expect(calls.count()).toBe(1);
expect(evt).toBeUndefined();
});

it('should not run perf timers for one time template bindings', function() {
var elt = angular.element(
'<div>' +
'<span>{{::a}}</span>' +
'<button ng-click="a = \'bar\'">Set</button>' +
'</div>'
);
scope.a = 'foo';
var view = $compile(elt)(scope);
scope.$apply();
var $binding = view.find('span');
var $button = view.find('button');

$button.triggerHandler('click');
scope.$apply();
expect($binding.text()).toBe('foo');
describe('one-time expressions', function() {
// Helpers
function getDigestCallArgs() {
var allArgs = hint.emit.calls.allArgs();
var digestCallArgs = allArgs.filter(function(args) {
return args[0] === 'scope:digest';
});

return digestCallArgs;
}

function countWatchEvents(args) {
var events = args[1].events;
var watchEvents = events.filter(function(evt) {
return evt.eventType === 'scope:watch';
});

return watchEvents.length;
}

it('should correctly trigger perf timers when passed to `$watch`', function() {
var calls = hint.emit.calls;
var args;

var reactions = [0, 0, 0];
var exps = [
'::c.d',
' ::c.d ',
' :: c.d '
].forEach(function(exp, idx) {
scope.$watch(exp, function(v) { reactions[idx]++; });
});

expect(calls.count()).toBe(0);

scope.$apply();
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(6); // Initial $digest: 2 loops
expect(reactions).toEqual([1, 1, 1]); // Initial $digest always calls listeners

calls.reset();
scope.$apply();
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(3); // No change: 1 loop
expect(reactions).toEqual([1, 1, 1]); // No change: listeners not called

calls.reset();
scope.$apply('c.d = "foo"');
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(6); // First change: 2 loops
expect(reactions).toEqual([2, 2, 2]); // First change to defined value calls listeners

calls.reset();
scope.$apply('c.d = "bar"');
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(0); // Already settled: 0 loops
expect(reactions).toEqual([2, 2, 2]); // Already settled: listeners not called
});

it('should correctly trigger perf timers when used in template bindings', function() {
var calls = hint.emit.calls;
var args;

$compile(
'<div>' +
// Interpolation in node text: 6 bindings (1 + 1 + 1 + 3)
'<span>{{::c.d}}</span>' +
'<span>{{ ::c.d }}</span>' +
'<span>{{ :: c.d }}</span>' +
'<span>{{::c.d}}{{ ::c.d }}{{ :: c.d }}</span>' +

// Interpolation in attribute value: 6 bindings (1 + 1 + 1 + 3)
'<span class="{{::c.d}}"></span>' +
'<span class="{{ ::c.d }}"></span>' +
'<span class="{{ :: c.d }}"></span>' +
'<span class="{{::c.d}}{{ ::c.d }}{{ :: c.d }}"></span>' +

// Expressions: 3 bindings (1 + 1 + 1)
'<span ng-if="::c.d"></span>' +
'<span ng-if=" ::c.d "></span>' +
'<span ng-if=" :: c.d "></span>' +

// Total: 15 watchers (6 + 6 + 3)
'</div>'
)(scope);

calls.reset();
scope.$apply();
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(30); // Initial $digest: 2 loops

calls.reset();
scope.$apply();
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(15); // No change: 1 loop

calls.reset();
scope.$apply('c.d = "foo"');
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(30); // First change: 2 loops

calls.reset();
scope.$apply('c.d = "bar"');
args = getDigestCallArgs();
expect(args.length).toBe(1);
expect(countWatchEvents(args[0])).toBe(0); // Already settled: 0 loops
});
});
}

Expand Down