File Metrics for TypeScript (TS),TypeScript JSX (TSX) and flow-annotated JavaScript

This document outlines the definition of file metrics for TypeScript (TS), TypeScript JSX (TSX) and flow-annotated JavaScript.

complexity

The "complexity" metric counts:

if and else if statements
ternary expressions and nullish coalescing operators
for...of, for await...of, for...in,while and do...while loops
case labels in switch-statements
catch blocks
logical binary operations && and ||
everything counted for the "functions" metric

It does not count:

.catch() method call for Promises
.forEach() method call for iterables and other built-in functions

functions

The "functions" metric counts:

static initialization blocks
method declarations in classes, abstract classes and interfaces
static methods, constructors, getters and setters
functions declared with the keyword function
arrow functions
interface/abstract methods (signatures)

classes

The "classes" metric counts:

declarations of classes, abstract classes, interfaces and enums
type aliases declaration with one single object type literal e.g. type ObjectType = { message: string};

It does not count:

other type aliases like
- type Union = {a: 1} & {b: 2};
- type Intersect = {a: 1} | {b: 2};
- type Tuple = [name: string, age: number];
- type AliasType = number;

lines_of_code, comment_lines, real_lines_of_code and keywords_in_comments