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Command Module Optimization Pattern ​

Performance Impact ​

Before optimization: ~1567ms
After optimization: ~916ms
Improvement: 651ms (41.5% faster!)

The Problem ​

Command modules were importing the full base.js at module level just to access metadata utilities like:

  • base.bundle.getText() - for internationalized strings
  • base.getBuilder() - for yargs builder configuration

This caused heavy dependencies to load even for simple --help commands:

  • sap-hdb-promisfied (180ms)
  • @inquirer/prompts (176ms)
  • terminal-kit (138ms)
  • ora (70ms)

The Solution ​

Separate command metadata (loaded early) from implementation (loaded on execution):

1. Use base-lite.js for Metadata ​

javascript
// OLD - loads all heavy dependencies
import * as base from '../utils/base.js'

export const describe = base.bundle.getText("tables")
export const builder = base.getBuilder({ /* options */ })

// NEW - only loads essentials
import * as baseLite from '../utils/base-lite.js'

export const describe = baseLite.bundle.getText("tables")
export const builder = baseLite.getBuilder({ /* options */ })

2. Lazy-Load Heavy Modules in Handler ​

javascript
// OLD - imported at module level
import * as base from '../utils/base.js'
import dbClientClass from "../utils/database/index.js"

export async function handler(argv) {
  base.promptHandler(argv, getTables, inputPrompts)
}

// NEW - imported only when handler executes
export async function handler(argv) {
  const base = await import('../utils/base.js')
  base.promptHandler(argv, getTables, inputPrompts)
}

3. Lazy-Load in Implementation Functions ​

javascript
// OLD - uses module-level imports
export async function getTables(prompts) {
  base.debug('getTables')
  const dbClient = await dbClientClass.getNewClient(prompts)
  // ...
}

// NEW - imports only when function executes
export async function getTables(prompts) {
  const base = await import('../utils/base.js')
  const dbClientModule = await import("../utils/database/index.js")
  const dbClientClass = dbClientModule.default
  
  base.debug('getTables')
  const dbClient = await dbClientClass.getNewClient(prompts)
  // ...
}

Complete Example: bin/tables.js ​

See bin/tables.js for the complete optimized implementation.

When to Apply This Pattern ​

Apply this optimization to any command module that:

  • Uses base.bundle.getText() or base.getBuilder()
  • Imports heavy dependencies like database clients, UI libraries, etc.
  • Is frequently accessed (common commands benefit most)

Benefits ​

  1. Faster CLI startup - Only loads what's needed for the requested operation
  2. Lower memory footprint - Heavy modules stay unloaded for simple operations
  3. Better user experience - Especially noticeable on Windows where Node.js startup is slower
  4. Backwards compatible - No changes to command behavior or API

Files Modified ​

Core Files ​

  • utils/base-lite.js - Lightweight utilities (bundle, getBuilder, colors, debug)
  • bin/cli.js - Lazy command loading based on requested command
  • bin/index.js - Proper promise resolution for command modules

Example Command (Pattern Template) ​

  • bin/tables.js - Reference implementation showing the optimization pattern