LAB TS Utils

A Collection of helpful tools for Typescript projects.

Install

NPM:

npm install @lukebechtel/lab-ts-utils

YARN:

yarn add @lukebechtel/lab-ts-utils

Functions

fixIndent

This function detects the minimum indentation level of each line and removes it. It reads over all lines, identifies the minimum indentation level, and strips all indentation before this level.

Usage

Simplifying Indentation

import { fixIndent } from '@lukebechtel/lab-ts-utils';

const str = `
    Hello,
        World!
    Have a good day.`;

console.log(fixIndent(str));

// Expected output:
// Hello,
//     World!
// Have a good day.

jwtBearerify

Prepends "Bearer" to a JWT token if it doesn't already start with "Bearer".

Usage

Adding Bearer Prefix

import { jwtBearerify } from '@lukebechtel/lab-ts-utils';

const token = 'abc.xyz.123';
console.log(jwtBearerify(token));

// Expected output:
// Bearer abc.xyz.123

mergeDeep

Uses lodash mergeWith to produce a deeply merged object from provided objects.

Usage

Deep Merging

import { mergeDeep } from '@lukebechtel/lab-ts-utils';

const obj1 = { a: [1], b: 2 };
const obj2 = { a: [3], c: 4 };

console.log(mergeDeep({toMerge: [obj1, obj2]}));

// Expected output:
// { a: [1, 3], b: 2, c: 4 }

notEmpty

This function checks if an item has some value. It narrows down the type from TValue | null | undefined to TValue, allowing TypeScript to know that the value is not null or undefined.

Usage

Checking Non-Empty Values

import { notEmpty } from '@lukebechtel/lab-ts-utils';

const value1 = undefined;
const value2 = 'Hello, World!';
console.log(notEmpty(value1)); // Expected output: false
console.log(notEmpty(value2)); // Expected output: true

prefixAllLines

This function adds a given prefix to the start of each line in a given string.

Usage

Adding Prefix to Each Line

import { prefixAllLines } from '@lukebechtel/lab-ts-utils';

const str = `Hello,
World!
Have a good day.`;
const prefix = '>> ';

console.log(prefixAllLines(prefix, str));

// Expected output:
// >> Hello,
// >> World!
// >> Have a good day.

You can replace '@lukebechtel/lab-ts-utils' with the actual name of your library. Also, replace the dummy variables and strings with actual examples that you wish to use.

createSimpleLogger

This function creates a simple logger with customizable prefixing and logging functions. You may use rawString, simpleString, or a function as a prefix to your log statements. Logging functions are also customizable and will default to appropriate console functions if no alternatives are provided.

Usage

Basic Logger

let logger = createSimpleLogger({}); // creates a logger with no prefix and default console logging

logger.log("log this");  // console output: "log this"

Logger with Raw String Prefix

let logger = createSimpleLogger({
    prefix: {
        type: 'rawString',
        rawString: 'raw'
    }
}); 

logger.log("log this");  // console output: "raw log this"

Logger with Simple String Prefix

let logger = createSimpleLogger({
    prefix: {
        type: 'simpleString',
        simpleString: 'simple'
    }
}); 

logger.log("log this");  // console output: "[simple]: log this"

Logger with Function Prefix

let logger = createSimpleLogger({
    prefix: {
        type: 'function',
        func: ({logType, logArgs}) => `[${logType.toUpperCase()}|${logArgs.length} arguments]: `
    }
}); 

logger.log("log this", "and this");  // console output: "[LOG|2 arguments]: log this and this"

trimAllLines

This function receives a multi-line string and trims the whitespace at the start and end of each line.

Usage

Trimming All Lines

let str = "     Line 1     \n     Line 2     ";
let trimmedStr = trimAllLines(str);

console.log(trimmedStr);  // console output: "Line 1\nLine 2"

trimLines

This function adjusts the indentation of a block string and optionally removes leading and trailing blank line blocks.

Usage

Adjusting Indentation and Removing Trailing Blank Lines

let str = "     Line 1\n     Line 2\n  \n";
let trimmedStr = trimLines(str, { trimVerticalEnd: true });

console.log(trimmedStr);  // console output: "Line 1\nLine 2"

tryUntilAsync

This function repeatedly executes a promise-returning function until it resolves or reaches a stopping condition.

Usage

Resolving Once the Promise is Successful

let attempts = 0;
let maxAttempts = 3;

let result = await tryUntilAsync({
    func: async () => {
        attempts++;
        if (attempts === maxAttempts) {
            return "Success"
        }
        else {
            throw new Error("Fail");
        }
    },
    tryLimits: {
        maxAttempts
    }
});

console.log(result);  // console output: "Success"

Resolving Based on a Specific Stop Condition

let attempts = 0;
let maxAttempts = 3;

let result = await tryUntilAsync({
    func: async () => {
        attempts++;
        return attempts;
    },
    stopCondition: (result: number) => result === maxAttempts,
    tryLimits: {
        maxAttempts
    }
});

console.log(result); // console output: 3

Using a Customized Delay Function

let start = Date.now();
let delayInSec = 2;

let result = await tryUntilAsync({
    func: async () => "Success",
    delay: {
        delayFunction: () => {
            return new Promise(resolve => setTimeout(resolve, delayInSec * 1000));
        }
    }
});

let end = Date.now();

console.log(result); // console output: "Success"
console.log(`Time elapsed: ${(end-start)/1000} seconds`); // console output: "Time elapsed: 2 seconds"

Please note that it's possible to encounter a TryUntilTimeoutError if the maximum number of attempts is reached or if the maximum time is exceeded without a successful result.