Modules and metrics

September 18, 2023 · View on GitHub

This file describes all phantomas modules (37 of them) and 191 metrics that they emit.

When applicable, offender example is provided.

ajaxRequests

Analyzes AJAX requests

`ajaxRequests`

number of AJAX requests (number, with offenders)

{
  "url": "/static/style.css",
  "method": "POST"
}

`synchronousXHR`

number of synchronous XMLHttpRequest (number, with offenders)

{
  "url": "inline-css.html",
  "method": "GET"
}

alerts

Meters number of invocations of window.alert, window.confirm, and window.prompt.

`windowAlerts`

number of calls to window.alert (number, with offenders)

"Oh dear!"

`windowConfirms`

number of calls to window.confirm (number, with offenders)

"Oh dear?"

`windowPrompts`

number of calls to window.prompt (number, with offenders)

"What's your name, dear?"

analyzeCss

Adds CSS complexity metrics using analyze-css npm module. Run phantomas with --analyze-css option to use this module

`cssBase64Length`

total length of base64-encoded data in CSS source (will warn about base64-encoded data bigger than 4 kB) (bytes, with offenders)

`cssColors`

number of unique colors used in CSS (number, with offenders)

`cssComments`

number of comments in CSS source (number, with offenders)

`cssCommentsLength`

length of comments content in CSS source (bytes)

`cssComplexSelectorsByAttribute`

number of selectors with complex matching by attribute (e.g. [class$="foo"]) (number, with offenders)

`cssDeclarations`

number of declarations (e.g. .foo, .bar { color: red } is counted as one declaration - color: red) (number, with offenders)

`cssDuplicatedProperties`

number of CSS property definitions duplicated within a selector (number, with offenders)

`cssDuplicatedSelectors`

number of CSS selectors defined more than once in CSS source (number, with offenders)

`cssEmptyRules`

number of rules with no properties (e.g. .foo { }) (number, with offenders)

`cssExpressions`

number of rules with CSS expressions (e.g. expression( document.body.clientWidth > 600 ? "600px" : "auto" )) (number, with offenders)

`cssImportants`

number of properties with value forced by !important (number, with offenders)

`cssImports`

number of @import rules (number, with offenders)

`cssInlineStyles`

number of inline styles (number)

`cssLength`

length of CSS source (in bytes) (bytes, with offenders)

`cssMediaQueries`

number of media queries (e.g. @media screen and (min-width: 1370px)) (number, with offenders)

`cssMultiClassesSelectors`

number of selectors with multiple classes (e.g. span.foo.bar) (number, with offenders)

`cssNotMinified`

set to 1 if the provided CSS is not minified (number, with offenders)

`cssOldIEFixes`

number of fixes for old versions of Internet Explorer (e.g. * html .foo {} and .foo { *zoom: 1 }) (number, with offenders)

`cssOldPropertyPrefixes`

number of properties with no longer needed vendor prefix, powered by data provided by autoprefixer (e.g. --moz-border-radius) (number, with offenders)

`cssParsingErrors`

number of CSS files (or embeded CSS) that failed to be parse by analyze-css (number, with offenders)

{
  "url": "[inline CSS]",
  "value": {
    "message": "Empty sub-selector",
    "position": {
      "end": {
        "column": 43,
        "line": 2
      },
      "source": "undefined",
      "start": {
        "column": 14,
        "line": 2
      }
    }
  }
}

`cssQualifiedSelectors`

number of qualified selectors (e.g. header#nav, .foo#bar, h1.title) (number, with offenders)

`cssRedundantBodySelectors`

number of redundant body selectors (e.g. body .foo, section body h2, but not body > h1) (number, with offenders)

`cssRules`

number of rules (e.g. .foo, .bar { color: red } is counted as one rule) (number, with offenders)

`cssSelectorLengthAvg`

average length of selector (e.g. for .foo .bar, #test div > span { color: red } will be set as 2.5) (number, with offenders)

`cssSelectors`

number of selectors (e.g. .foo, .bar { color: red } is counted as two selectors - .foo and .bar) (number, with offenders)

`cssSelectorsByAttribute`

number of selectors by attribute (e.g. .foo[value=bar]) (number)

`cssSelectorsByClass`

number of selectors by class (number)

`cssSelectorsById`

number of selectors by ID (number)

`cssSelectorsByPseudo`

number of pseudo-selectors (e,g. :hover) (number)

`cssSelectorsByTag`

number of selectors by tag name (number)

`cssSpecificityClassAvg`

average specificity for class, pseudo-class or attribute (number, with offenders)

`cssSpecificityClassTotal`

total specificity for class, pseudo-class or attribute (number)

`cssSpecificityIdAvg`

average specificity for ID (number, with offenders)

`cssSpecificityIdTotal`

total specificity for ID (number)

`cssSpecificityTagAvg`

average specificity for element (number, with offenders)

`cssSpecificityTagTotal`

total specificity for element (number)

`redundantChildNodesSelectors`

number of redundant child nodes selectors (number, with offenders)

analyzeImages

Adds Responsive Images metrics using analyze-images npm module. Run phantomas with --analyze-images option to use this module

`imagesExcessiveDensity`

number of images that could be served smaller as the human eye can hardly see the difference (number, with offenders)

`imagesNotOptimized`

number of loaded images that could be lighter it optimized (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/example.svg",
  "fileSize": 464,
  "newFileSize": 290
}

`imagesOldFormat`

number of loaded images that could benefit from new generation formats (WebP or AVIF) (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/mdn.png",
  "fileSize": 20386,
  "newFileSize": 7011,
  "webpSize": 10876,
  "avifSize": 7011
}

`imagesScaledDown`

number of loaded images scaled down when displayed (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/mdn.png?nocache=1",
  "fileSize": 18462,
  "naturalWidth": 600,
  "naturalHeight": 529,
  "newFileSize": 6793,
  "newWidth": 300,
  "newHeight": 265,
  "dpr": 1
}

`imagesWithIncorrectSizesParam`

number of responsive images with an improperly set sizes parameter (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/mdn.png?nocache=6",
  "sizesAttribute": "calc(99vw - 3px - 1em)",
  "convertedInPx": 773,
  "displayWidth": 300
}

`imagesWithoutDimensions`

number of nodes without both width and height attribute (number, with offenders)

{
  "path": "img#img",
  "src": "http://0.0.0.0:8888/static/mdn.png"
}

assetsTypes

Analyzes number of requests and sizes of different types of assets

`base64Count`

number of base64 encoded "responses" (no HTTP request was actually made) (number, with offenders)

`base64Size`

size of base64 encoded responses (bytes)

`cssCount`

number of CSS responses (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/style.css",
  "size": 320
}

`cssSize`

size of CSS responses (with compression) (bytes)

`htmlCount`

number of HTML responses (number, with offenders)

{
  "url": "http://127.0.0.1:8888/dom-operations.html",
  "size": 946
}

`htmlSize`

size of HTML responses (with compression) (bytes)

`imageCount`

number of image responses (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/blank.gif",
  "size": 342
}

`imageSize`

size of image responses (with compression) (bytes)

`jsCount`

number of JS responses (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/jquery-2.1.1.min.js",
  "size": 29734
}

`jsSize`

size of JS responses (with compression) (bytes)

`jsonCount`

number of JSON responses (number, with offenders)

{
  "url": "http://127.0.0.1:8888/foo.json",
  "size": 345
}

`jsonSize`

size of JSON responses (with compression) (bytes)

`otherCount`

number of other responses (number, with offenders)

{
  "url": "http://0.0.0.0:8888/favicon.ico",
  "size": 103
}

`otherSize`

size of other responses (with compression) (bytes)

`videoCount`

number of video responses (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/stickman.webm",
  "size": 3750
}

`videoSize`

size of video responses (with compression) (bytes)

`webfontCount`

number of web font responses (number, with offenders)

`webfontSize`

size of web font responses (with compression) (bytes)

blockDomains

Aborts requests to external resources or given domains Does not emit any metrics

`blockedRequests`

number of requests blocked due to domain filtering (number, with offenders)

"http://code.jquery.com/jquery-1.11.1.js"

cacheHits

Analyzes Age and X-Cache headers from caching servers like Squid or Varnish

`cacheHits`

number of cache hits (number, with offenders)

`cacheMisses`

number of cache misses (number, with offenders)

`cachePasses`

number of cache passes (number, with offenders)

caching

Analyzes HTTP caching headers

`cachingDisabled`

number of responses with caching disabled (max-age=0) (number, with offenders)

"http://0.0.0.0:8888/static/mdn-no-cache.png"

`cachingNotSpecified`

number of responses with no caching header sent (no Cache-Control header) (number, with offenders)

"http://0.0.0.0:8888/static/jquery-1.4.4.min.js"

`cachingTooShort`

number of responses with too short (less than a week) caching time (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/mdn.png",
  "ttl": 86400
}

`cachingUseImmutable`

number of responses with a long TTL that can benefit from Cache-Control: immutable (number, with offenders)

{
  "url": "http://code.jquery.com/jquery-1.4.4.js",
  "ttl": 315360000
}

`oldCachingHeaders`

number of responses with old, HTTP 1.0 caching headers (Expires and Pragma) (number, with offenders)

{
  "url": "http://0.0.0.0:8888/_make_docs.html",
  "headerName": "expires",
  "value": "Wed, 16 Aug 2023 12:28:56 GMT"
}

console

Meters number of console logs

`consoleMessages`

number of calls to console.* functions (number, with offenders)

"log:[\"Hi!\"]"

cookies

cookies metrics

`cookiesRecv`

length of cookies received in HTTP responses (bytes)

`cookiesSent`

length of cookies sent in HTTP requests (bytes)

`documentCookiesCount`

number of cookies in document.cookie (number)

`documentCookiesLength`

length of document.cookie (bytes)

`domainsWithCookies`

number of domains with cookies set (number, with offenders)

cpuTasks

`layoutCount`

total number of full or partial page layout (number)

`layoutDuration`

combined durations of all page layouts (ms)

`recalcStyleCount`

total number of page style recalculations (number)

`recalcStyleDuration`

combined duration of style recalculations (ms)

`scriptDuration`

combined duration of JavaScript execution (ms)

`taskDuration`

combined duration of all tasks performed by the browser (ms)

documentHeight

Measure document height

`documentHeight`

the page height (px)

domComplexity

Analyzes DOM complexity

`DOMelementMaxDepth`

maximum level on nesting of HTML element node (number, with offenders)

"body > script[0]"

`DOMelementsCount`

total number of HTML element nodes (number)

`DOMidDuplicated`

number of duplicated IDs found in DOM (number, with offenders)

{
  "id": "img",
  "count": 2
}

`bodyHTMLSize`

the size of body tag content (document.body.innerHTML.length) (bytes)

`commentsSize`

the size of HTML comments on the page (bytes, with offenders)

`iframesCount`

number of iframe nodes (number, with offenders)

{
  "element": "body > iframe[1]",
  "url": "http://127.0.0.1:8888/image-scaling.html"
}

`nodesWithInlineCSS`

number of nodes with inline CSS styling (with style attribute) (number, with offenders)

{
  "css": "color: blue",
  "node": "p#foo"
}

`whiteSpacesSize`

the size of text nodes with whitespaces only (bytes)

domHiddenContent

Analyzes DOM hidden content

`hiddenContentSize`

the size of content of hidden elements on the page (with CSS display: none) (bytes, with offenders)

`hiddenImages`

number of hidden images that can be lazy-loaded (number, with offenders)

"http://127.0.0.1:8888/static/mdn.png"

domMutations

Analyzes DOM changes via MutationObserver API

`DOMmutationsAttributes`

number of DOM nodes attributes changes (number, with offenders)

{
  "attribute": "style",
  "node": "body"
}

`DOMmutationsInserts`

number of node inserts (number, with offenders)

{
  "node": "strong[0]",
  "target": "p#foo"
}

`DOMmutationsRemoves`

number of node removes (number, with offenders)

{
  "node": "span#delete",
  "target": "body"
}

domQueries

Analyzes DOM queries done via native DOM methods

`DOMinserts`

number of DOM nodes inserts (number, with offenders)

{
  "append": "html > div[2]",
  "node": "html"
}

`DOMqueries`

number of all DOM queries (number, with offenders)

`DOMqueriesAvoidable`

number of repeated uses of a duplicated query (number)

`DOMqueriesByClassName`

number of document.getElementsByClassName calls (number, with offenders)

{
  "class": "barr",
  "node": "body"
}

`DOMqueriesById`

number of document.getElementById calls (number, with offenders)

{
  "id": "foo",
  "node": "#document"
}

`DOMqueriesByQuerySelectorAll`

number of document.querySelector(All) calls (number, with offenders)

{
  "selector": ".TEST",
  "node": "div"
}

`DOMqueriesByTagName`

number of document.getElementsByTagName calls (number, with offenders)

{
  "tag": "*",
  "node": "div"
}

`DOMqueriesDuplicated`

number of DOM queries called more than once (number, with offenders)

{
  "query": "id \"#foo\" (in #document)",
  "count": 2
}

`DOMqueriesWithoutResults`

number of DOM queries that returned nothing (number, with offenders)

{
  "query": "#script1692102537022",
  "node": "#document",
  "function": "getElementById"
}

domains

Domains monitor

`domains`

number of domains used to fetch the page (number, with offenders)

{
  "domain": "127.0.0.1",
  "requests": 2
}

`maxRequestsPerDomain`

maximum number of requests fetched from a single domain (number)

`medianRequestsPerDomain`

median of number of requests fetched from each domain (number)

events

Analyzes events bound to DOM elements

`eventsBound`

number of EventTarget.addEventListener calls (number, with offenders)

{
  "eventType": "load",
  "path": "window"
}

`eventsDispatched`

number of EventTarget.dispatchEvent calls (number, with offenders)

{
  "eventType": "click",
  "path": "body > div#foo > span.bar"
}

`eventsScrollBound`

number of scroll event bounds (number, with offenders)

{
  "element": "#document"
}

globalVariables

Counts global JavaScript variables

`globalVariables`

number of JS globals variables (number, with offenders)

"jQuery"

`globalVariablesFalsy`

number of JS globals variables with falsy value (number, with offenders)

{
  "name": "falsy",
  "value": false
}

headers

Analyzes HTTP headers in both requests and responses

`headersBiggerThanContent`

number of responses with headers part bigger than the response body (number, with offenders)

`headersCount`

number of requests and responses headers (number)

`headersRecvCount`

number of headers received in responses (number)

`headersRecvSize`

size of received headers (bytes)

`headersSentCount`

number of headers sent in requests (number)

`headersSentSize`

size of sent headers (bytes)

`headersSize`

size of all headers (bytes)

jQuery

Analyzes jQuery activity

`jQueryDOMReads`

number of DOM read operations (number, with offenders)

{
  "functionName": "css",
  "arguments": "[\"color\"]",
  "contextPath": "body > div#foo > span.bar"
}

`jQueryDOMWriteReadSwitches`

number of read operations that follow a series of write operations (will cause repaint and can cause reflow) (number, with offenders)

{
  "functionName": "css",
  "arguments": "[\"color\"]",
  "contextPath": "body > div#foo > span.bar"
}

`jQueryDOMWrites`

number of DOM write operations (number, with offenders)

{
  "functionName": "css",
  "arguments": "[{\"color\":\"red\",\"background\":\"green\"}]",
  "contextPath": "body > div#foo > span.bar"
}

`jQueryEventTriggers`

number of jQuery event triggers (number, with offenders)

{
  "type": "click",
  "element": "body > div#foo > span.bar"
}

`jQueryOnDOMReadyFunctions`

number of functions bound to onDOMReady event (number, with offenders)

"HTMLDocument.DOMContentLoaded (http://code.jquery.com/jquery-1.4.4.js:875:10)"

`jQuerySizzleCalls`

number of calls to Sizzle (including those that will be resolved using querySelectorAll) (number, with offenders)

{
  "selector": "#foo .bar",
  "element": "#document"
}

`jQueryVersion`

version of jQuery framework (if loaded) (string)

`jQueryVersionsLoaded`

number of loaded jQuery "instances" (even in the same version) (number, with offenders)

{
  "version": "2.1.1",
  "url": "http://127.0.0.1:8888/static/jquery-2.1.1.min.js"
}

`jQueryWindowOnLoadFunctions`

number of functions bound to windowOnLoad event (number, with offenders)

"http://127.0.0.1:8888/jquery.html:49:13"

javaScriptBottlenecks

Reports the use of functions known to be serious performance bottlenecks in JS Run phantomas with --spy-eval to count eval() calls (see issue #467)

`documentWriteCalls`

number of calls to either document.write or document.writeln (number, with offenders)

{
  "message": "document.write() used",
  "caller": "http://127.0.0.1:8888/bottlenecks.html:11:11"
}

`evalCalls`

number of calls to eval (either direct or via setTimeout / setInterval) (number, with offenders)

{
  "message": "eval() called directly",
  "caller": "http://127.0.0.1:8888/bottlenecks.html:8:2"
}

jserrors

Meters the number of page errors, and provides traces as offenders for "jsErrors" metric

`jsErrors`

number of JavaScript errors (number, with offenders)

"unknown_function_called is not defined - "

keepAlive

Analyzes if HTTP responses keep the connections alive.

`closedConnections`

number of requests not keeping the connection alive and slowing down the next request (number, with offenders)

lazyLoadableImages

Analyzes images and detects which one can be lazy-loaded (are below the fold)

`lazyLoadableImagesBelowTheFold`

number of images displayed below the fold that can be lazy-loaded (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/blank.gif",
  "node": "body > img#dot",
  "offset": 900
}

localStorage

localStorage metrics

`localStorageEntries`

number of entries in local storage (number, with offenders)

"foo"

mainRequest

Analyzes bits of data pertaining to the main request only

`statusCodesTrail`

comma-separated list of HTTP status codes that main request followed through (could contain a single element if the main request is a terminal one) (string)

navigationTiming

Emits "milestone" event on Navigation Timing related events:

domContentLoaded
domInteractive
domComplete Code taken from windowPerformance module

protocols

Checks versions of HTTP and TLS protocols

{
  "domain": "https://127.0.0.1",
  "httpVersion": "http/1.1",
  "requests": 2
}

`oldTlsProtocol`

number of domains using TLS 1.2 (number, with offenders)

{
  "domain": "https://127.0.0.1",
  "tlsVersion": "TLS 1.2",
  "beforeDomReady": true
}

redirects

Analyzes HTTP redirects

Simple HTTP requests monitor and analyzer

{
  "url": "http://127.0.0.1:8888/dom-operations.html",
  "bodySize": 2094,
  "transferedSize": 946
}

"http://127.0.0.1:8888/not_found/foo.js"

`postRequests`

number of POST requests (number, with offenders)

"http://127.0.0.1:8888/static/style.css"

`requests`

total number of HTTP requests made (number, with offenders)

{
  "url": "http://127.0.0.1:8888/not-found.html",
  "type": "html",
  "size": 380
}

requestsStats

Analyzes HTTP requests and generates stats metrics

`biggestLatency`

the time to the first byte of the slowest response (ms, with offenders)

{
  "url": "http://0.0.0.0:8888/static/mdn-short-cache.png",
  "timeToFirstByte": 31.697000000000003
}

`biggestResponse`

the size of the biggest response (bytes, with offenders)

{
  "url": "http://127.0.0.1:8888/headers.html",
  "size": 856
}

`fastestResponse`

the time to the last byte of the fastest response (ms, with offenders)

{
  "url": "http://0.0.0.0:8888/foo.json",
  "timeToLastByte": 0.004929000046104193
}

{
  "url": "http://code.jquery.com/jquery-1.4.4.js",
  "timeToLastByte": 0.08683400019071996
}

`smallestLatency`

the time to the first byte of the fastest response (ms, with offenders)

{
  "url": "http://0.0.0.0:8888/foo.json",
  "timeToFirstByte": 3.077
}

`smallestResponse`

the size of the smallest response (bytes, with offenders)

{
  "url": "http://127.0.0.1:8888/static/blank.gif",
  "size": 342
}

requestsTo

Number of requests it took to make the page enter DomContentLoaded and DomComplete states accordingly

`domainsToDomComplete`

number of domains used to make the page reach DomComplete state (number, with offenders)

{
  "domain": "127.0.0.1",
  "requests": 2
}

`domainsToDomContentLoaded`

number of domains used to make the page reach DomContentLoaded state (number, with offenders)

{
  "domain": "127.0.0.1",
  "requests": 2
}

Analyzes static assets (CSS, JS and images)

`assetsNotGzipped`

number of static assets that were not gzipped (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/jquery-1.4.4.min.js",
  "contentType": "application/javascript"
}

`assetsWithCookies`

number of static assets requested from domains with cookie set (number, with offenders)

`assetsWithQueryString`

number of static assets requested with query string (e.g. ?foo) in URL (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/mdn.png?cb=123",
  "contentType": "image/png"
}

`multipleRequests`

number of static assets that are requested more than once (number, with offenders)

`smallCssFiles`

number of CSS assets smaller than 2 KiB that can be inlined or merged (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/style.css",
  "size": 320
}

`smallImages`

number of images smaller than 2 KiB that can be base64 encoded (number, with offenders)

{
  "url": "http://127.0.0.1:8888/static/blank.gif",
  "size": 342
}

`smallJsFiles`

number of JS assets smaller than 2 KiB that can be inlined or merged (number, with offenders)

timeToFirst

Provides metrics for time to first image, CSS and JS file

`timeToFirstCss`

time it took to receive the last byte of the first CSS (ms, with offenders)

`timeToFirstImage`

time it took to receive the last byte of the first image (ms, with offenders)

"http://0.0.0.0:8888/static/mdn.png received in NaN ms"

`timeToFirstJs`

time it took to receive the last byte of the first JS (ms, with offenders)

"http://0.0.0.0:8888/static/jquery-1.4.4.min.js received in NaN ms"

timeToFirstByte

Takes a look at "time to first (last) byte" metrics

Measure when the page reaches certain states

This file is auto-generated from code comments. Please run npm run make-docs to update it.