TraceLib
========

This library provides a set of models from the devtools-frontend code base in order to parse trace log files.

__Note:__ This is early development and not ready to be consumed yet!

Installation

To install the package to your project, run:

``sh
$ npm install --save tracelib
`

Usage

getSummary

Fetch total time-durations of scripting, rendering, painting from tracelogs.

!Summary Data

`js
import Tracelib from 'tracelib'
import JANK_TRACE_LOG from './jankTraceLog.json'

const tasks = new Tracelib(JANK_TRACE_LOG)
const summary = tasks.getSummary()
console.log(summary)

/**
* output:
* {
* rendering: 847.373997092247,
* painting: 69.94999980926514,
* other: 9.896000564098358,
* scripting: 394.4800021648407,
* idle: 52.38300037384033,
* startTime: 289959855.634,
* endTime: 289961229.717
* }
`

getWarningCounts

Fetch amount of forced synchronous layouts and styles as well as long recurring handlers.

!Warning Counts

`js
import Tracelib from 'tracelib'
import JANK_TRACE_LOG from './jankTraceLog.json'

const tasks = new Tracelib(JANK_TRACE_LOG)
const counts = tasks.getWarningCounts()
console.log(counts)

/**
* {
* LongRecurringHandler: 13,
* ForcedStyle: 4684,
* ForcedLayout: 4683
* }
*/
`

getFPS

Fetch frames per second.

`js
import Tracelib from 'tracelib'
import JANK_TRACE_LOG from './jankTraceLog.json'

const tasks = new Tracelib(JANK_TRACE_LOG)
const fps = tasks.getFPS()
console.log(fps)

/**
* {
* times: [
* 289959949.734,
* 289959955.22,
* 289960052.234,
* 289960142.388,
* 289960233.175,
* 289960324.01,
* 289960416.646,
* 289960508.145,
* 289960600.602,
* 289960695.329,
* 289960790.75,
* 289960882.274,
* 289960977.634,
* 289961069.395
* ],
* values: [
* 182.2821727559685,
* 10.307790628308753,
* 11.092131244032895,
* 11.014792866762287,
* 11.00897231503525,
* 10.794939328106791,
* 10.929081197725838,
* 10.815838712204958,
* 10.556652274643293,
* 10.47987340271033,
* 10.926095888726774,
* 10.486577179634944,
* 10.897876006628481,
* 10.839990888916617
* ]
* }
*/
`

getMemoryCounters

Fetch data for JS Heap, Documents, Nodes, Listeners and GPU Memory from tracelogs.

!Memory Counters

`js
import Tracelib from 'tracelib'
import JANK_TRACE_LOG from './jankTraceLog.json'

const tasks = new Tracelib(JANK_TRACE_LOG)
const memoryInfo = tasks.getMemoryCounters()
console.log(memoryInfo)

/**
* output:
* { jsHeapSizeUsed:
* { times:
* [ 49970556.092,
* 49970557.846,
* 49970579.075,
* ... 193 more items ],
* values:
* [ 15307712,
* 15315152,
* 15318984,
* ... 193 more items ] },
* documents:
* { times:
* [ 49970556.092,
* 49970987.298,
* 49970997.59,
* 49971005.521,
* 49971062.064,
* 49971147.013,
* 49971156.296,
* 49971196.957,
* 49971259.352,
* 49972763.552,
* 49972764.108 ],
* values: [ 6, 7, 8, 9, 8, 6, 7, 6, 5, 6, 7 ] },
* nodes:
* { times:
* [ 49970556.092,
* 49970570.227,
* 49970946.325,
* ...
* 49973091.931 ],
* values:
* [ 4339,
* 5192,
* 6727,
* ...
* 4528 ] },
* jsEventListeners:
* { times:
* [ 49970556.092,
* 49970958.971,
* 49970987.298,
* ...
* 49972763.552 ],
* values:
* [ 101,
* 102,
* 103,
* ...
* 111 ] },
* gpuMemoryUsedKB: { times: [], values: [] } }
*/
`

getDetailStats

Fetch data (timestamp and values) of scripting, rendering, painting from tracelogs.

!Detail Data

`js
import Tracelib from 'tracelib'
import JANK_TRACE_LOG from './jankTraceLog.json'

const tasks = new Tracelib(JANK_TRACE_LOG)
const detail = tasks.getDetailStats()
console.log(detail)

/**
* output:
* {
* rendering: {
* times: [ 49970556.092, ..., 49972763.552 ],
* values: [1, ..., 5]
* },
* painting: {
* times: [ 49970556.092, ..., 49972763.552 ],
* values: [1, ..., 5]
* },
* other: {
* times: [ 49970556.092, ..., 49972763.552 ],
* values: [1, ..., 5]
* },
* scripting: {
* times: [ 49970556.092, ..., 49972763.552 ],
* values: [1, ..., 5]
* },
* range: {
* times: [ 289959855.634, 289961229.717 ],
* values: [ 289959855.634, 289961229.717 ]
* }
* }
`

Test

To test this package, run:

`sh
$ npm run test
``