phantomas/modules/domQueries/scope.js

Headless Chromium-based web performance metrics collector and monitoring tool

(function domQueriesScope(phantomas) {
  phantomas.log("domQueries: initializing page scope code");

  function querySpy(type, query, fnName, context, hasNoResults) {
    phantomas.emit("domQuery", type, query, fnName, context, hasNoResults); // @desc DOM query has been made

    phantomas.log("querySpy: " + query);
  }

  // selectors by element ID
  phantomas.spy(
    Document.prototype,
    "getElementById",
    function (results, id) {
      phantomas.incrMetric("DOMqueriesById");
      phantomas.addOffender("DOMqueriesById", {
        id,
        node: phantomas.getDOMPath(this),
      });
      querySpy("id", "#" + id, "getElementById", "#document", results === null);
    },
    true
  );

  // selectors by class name
  function selectorClassNameSpy(results, className) {
    var context = phantomas.getDOMPath(this);

    phantomas.incrMetric("DOMqueriesByClassName");
    phantomas.addOffender("DOMqueriesByClassName", {
      class: className,
      node: context,
    });
    querySpy(
      "class",
      "." + className,
      "getElementsByClassName",
      context,
      results.length === 0
    );
  }

  phantomas.spy(
    Document.prototype,
    "getElementsByClassName",
    selectorClassNameSpy,
    true
  );
  phantomas.spy(
    Element.prototype,
    "getElementsByClassName",
    selectorClassNameSpy,
    true
  );

  // selectors by tag name
  function selectorTagNameSpy(results, tagName) {
    var context = phantomas.getDOMPath(this);

    // querying by BODY and body is the same (issue #419)
    if (tagName) tagName = tagName.toLowerCase();

    phantomas.incrMetric("DOMqueriesByTagName");
    phantomas.addOffender("DOMqueriesByTagName", {
      tag: tagName,
      node: phantomas.getDOMPath(this),
    });
    querySpy(
      "tag name",
      tagName,
      "getElementsByTagName",
      context,
      results.length === 0
    );
  }

  phantomas.spy(
    Document.prototype,
    "getElementsByTagName",
    selectorTagNameSpy,
    true
  );
  phantomas.spy(
    Element.prototype,
    "getElementsByTagName",
    selectorTagNameSpy,
    true
  );

  // selector queries
  function selectorQuerySpy(results, selector) {
    var context = phantomas.getDOMPath(this);

    phantomas.incrMetric("DOMqueriesByQuerySelectorAll");
    phantomas.addOffender("DOMqueriesByQuerySelectorAll", {
      selector,
      node: context,
    });
    querySpy(
      "selector",
      selector,
      "querySelectorAll",
      context,
      results === null || results.length === 0
    );
  }

  phantomas.spy(Document.prototype, "querySelector", selectorQuerySpy, true);
  phantomas.spy(Document.prototype, "querySelectorAll", selectorQuerySpy, true);
  phantomas.spy(Element.prototype, "querySelector", selectorQuerySpy, true);
  phantomas.spy(Element.prototype, "querySelectorAll", selectorQuerySpy, true);

  // count DOM inserts
  function appendSpy(child) {
    // ignore appending to the node that's not yet added to DOM tree
    if (!this.parentNode) {
      return;
    }

    var destNodePath = phantomas.getDOMPath(this),
      appendedNodePath = phantomas.getDOMPath(child);

    // skip undefined nodes (issue #560)
    if (destNodePath === false) {
      return;
    }

    // don't count elements added to fragments as a DOM inserts (issue #350)
    // DocumentFragment > div[0]
    if (destNodePath.indexOf("DocumentFragment") === 0) {
      return;
    }

    phantomas.incrMetric("DOMinserts");
    phantomas.addOffender("DOMinserts", {
      append: appendedNodePath,
      node: destNodePath,
    });

    phantomas.log(
      'DOM insert: node "%s" appended to "%s"',
      appendedNodePath,
      destNodePath
    );
  }

  phantomas.spy(Node.prototype, "appendChild", appendSpy);
  phantomas.spy(Node.prototype, "insertBefore", appendSpy);

  phantomas.log("domQueries: page scope code initialized");
})(window.__phantomas);