javascript - How many watches are there in a page?

Question

I am doing performance testing in Angular and I want to know exactly how many watches are there in my page. Turns out there is no easy way to do this. Has anyone tried it yet?

Any help will be highly appreciated!

Answer 1

我有同样的问题。我创建了一个可以做到这一点的函数：

// get the watch count
// scopeHash is an optional parameter, but if you provide one, this function will modify it for later use (possibly debugging)
function getWatchCount (scope, scopeHash) {
    // default for scopeHash
    if (scopeHash === undefined) {
        scopeHash = {};
    }

    // make sure scope is defined and we haven't already processed this scope
    if (!scope || scopeHash[scope.$id] !== undefined) {
        return 0;
    }

    var watchCount = 0;

    if (scope.$$watchers) {
        watchCount = scope.$$watchers.length;
    }
    scopeHash[scope.$id] = watchCount;

    // get the counts of children and sibling scopes
    // we only need childHead and nextSibling (not childTail or prevSibling)
    watchCount+= getWatchCount(scope.$$childHead, scopeHash);
    watchCount+= getWatchCount(scope.$$nextSibling, scopeHash);

    return watchCount;
}

它将计算任何范围内的观察者数量。在根作用域上计算可能最有用，但您可以在任何作用域级别使用它（可能检查组件上的监视）。这是一个实际示例：http: //jsfiddle.net/S7APg/