log-spark v1.2.0

log-spark adds abstract syntax tree (AST) transformer functions for logging to Typescript. These function calls are evaluated at compile-time and only included in the generated JavaScript when certain conditions are met.

log-spark uses ts-patch to add transformer plugins to Typescript compilation and ts-node to run the modified compiler.

Example

// Logging macros take a domain and a message string
$logTrace('Storage', 'Initializing...');

// Messages are string literals and can use variables
$logInfo('Game', `Ready player ${playerName}!`);

// The domain parameter can be an object on which `.toString()` is called
$logWarn(oven, `Set to ${oven.degrees} Celcius`);

// You can also use `this` as the domain
$logError(this, `${this._drinks} is too many drinks!`);

// Fatal log messages throw an error by default
$logFatal('Map', 'City not found');

// This macro will output only when compiling in a development configuration (default)
let environment = 'production';
$devOnly(() => {
	environment = 'development';
});

// And this macro works the other way around
let moneyOwed = 100000;
$prodOnly(() => {
	moneyOwed = 0;
});

When the above is compiled, the following JavaScript is produced:

console.log("[TRACE] (Storage) Initializing...");

console.log("(Game)", `Ready player ${playerName}!`);

console.warn("(" + oven.toString() + ")", `Set to ${oven.degrees} degrees Celcius`);

console.error("(" + this.toString() + ")", `${this._drinks} is too many drinks!`);

(() => {
	throw new Error("(Map) City not found");
})();

let environment = 'production';
(() => {
	environment = 'development';
})();

let moneyOwed = 100000;

Logging macros

Configuration

Before you can build with log-spark, you must run npx ts-patch install on your project, and modify your tsconfig.json:

{
	"$schema": "http://json.schemastore.org/tsconfig",
	"compilerOptions": {
		"plugins": [
			{
				"transform": "log-spark"
				// See additional settings in the table below
			}
		],
		"typeRoots": [
			// Required for adding the macros to the global namespace
			"./node_modules/log-spark/dist"
		],
		"include": [
			// Required for the compiler to recognize the macros as global functions
			"./node_modules/log-spark/dist"
		],
	},
	"ts-node": {
		// NOTE: You must run `npx ts-patch install` first!
		"compiler": "ts-patch/compiler"
	}
}

The object in the plugins array takes these additional properties: