scope-utilities

A library that helps you replace multiple variables and statements into a single type-safe & functional expression.

Features

• Chaining
• Great Type Inference
• Async / Await Support

Installation

# pnpm
pnpm add --save scope-utilities

# npm
npm install --save scope-utilities

Usage

import { scope } from 'scope-utilities';

scope(VALUE).also(FUNC).value()

• Passes VALUE into first argument of FUNC
• Returns VALUE

Realistic Example

Contain changes to mutable objects:

const nearest_date = false;

const dateForNextWeek: Date = scope(new Date())
  .also((date) => {
      date.setDate(date.getDate() + 7)
  }).also(date => {
      if (nearest_date) {
          date.setHours(0)
          date.setMinutes(0)
          date.setSeconds(0)
          date.setMilliseconds(0)
      }
  }).value();

scope(VALUE).let(FUNC).value()

• Passes VALUE into first argument of FUNC
• Returns the result of FUNC

Realistic example

Conditionally building queries:

const query = await scope(
        startQuery()
    ).let((query) =>
        shuoldIncludeContactDetails()
          ? query.select(['id', 'email', 'COUNT(*) as post_count'])
          : query.select(['id', 'COUNT(*) as post_count'])
    ).let(async (query) => 
        await shouldReturnActiveOnly()
            ? query.where({ active: true })
            : query
    ).let((query) =>
        query.groupBy('id') // no need to await `query` here.
    ).let(query =>
        shouldSortBy() === 'post_count'
            ? query.orderBy('post_count')
            : shouldSortBy() === 'signup_time'
            ? query.orderBy('created_at')
            : query
    )
    .value();

const results = query.execute();

run(FUNC).value()

• Runs FUNC and returns the result
• You can chain it with other scope functions if you like.

const newUser = await run(async () => {
    return await queryUser();
}).let((user) => {
    return user.clone();
}).also((user) => {
    user.setName('John Doe');
}).let(async () => {
    return await user.save();
}).value();

License

MIT