ts-tracelytics

A Deno CLI tool to analyze Typescript build trace files and identify performance bottlenecks.

Features

• Parse Typescript (tsc) build trace files (generated with --generateTrace flag)
• Calculate build time metrics across various compilation phases
• Identify slowest operations, files, and module resolutions
• Categorize files by type and track processing statistics
• Output data as colorful terminal output or structured JSON

Motivation

If you need a way to easily get basic statistics about your Typescript builds, this is the thing. I'd also recommend checking out the official @typescript/analyze-trace tool.

Installation

This is a Deno application, so you need to have Deno installed on your system.

To use ts-tracelytics directly:

# Run directly with Deno
deno run jsr:@tichopad/ts-tracelytics your-trace.json --output json > stats.json

Alternatively, clone the repository and compile:

git clone https://github.com/tichopad/ts-tracelytics.git
cd ts-tracelytics
deno task compile
./build/ts-tracelytics your-trace.json

Usage

Generate a TypeScript Build Trace

First, generate a trace file from your TypeScript build:

tsc --generateTrace trace_output_dir

This creates a trace.json file in the specified directory.

Analyze the Trace

Analyze your trace file:

# Output to terminal (human-readable format)
deno run jsr:@tichopad/ts-tracelytics trace.json

# Output as JSON
deno run jsr:@tichopad/ts-tracelytics trace.json --output json > stats.json

Command Line Options

• Input file path: First positional argument (required)
• --output, -o: Output format (json or cli, default: cli)
• --help, -h: Show help information

Output Examples

Terminal Output (Default)

The default terminal output provides a formatted analysis including:

• Overall build statistics (total time, files processed)
• Top 5 slowest operations with timing details
• Top 5 slowest files with their primary operations
• File type distribution
• Module resolution statistics

Example:

TypeScript Build Trace Analysis

Overall Statistics
=================
Total build time: 2s 345ms
Total files processed: 128
Total unique operations: 15

Top 5 Slowest Operations
=======================
createProgram
  Total time: 1s 234ms
  Count: 1
  Average time: 1s 234ms

typeCheck
  Total time: 563ms
  Count: 128
  Average time: 4.4ms

...

JSON Output

When using --output json, the tool generates corresponding statistics as structured JSON:

{
  "totalTime": 2345678,
  "totalFiles": 128,
  "operationTimes": {
    "createProgram": {
      "totalTime": 1234567,
      "count": 1,
      "averageTime": 1234567
    },
    "typeCheck": {
      "totalTime": 563200,
      "count": 128,
      "averageTime": 4400
    },
    ...
  },
  "categoryTimes": { ... },
  "slowestFiles": [ ... ],
  "filesByType": { ... },
  "moduleResolution": { ... }
}

License

MIT