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@SisyphusZheng SisyphusZheng released this 17 May 04:12
0.18.2
9b66e7a

Changelog: v0.18.2

Release date: 2026-05-17
Release type: minor patch (CLI + project mutation)

Overview

v0.18.2 adds less add — a safe install flow for adding third-party Web
Component packages to LessJS projects. Every install is preceded by
validation (v0.18.1), so invalid packages are rejected before any files
are touched.

What's New

Safe Install Flow (@lessjs/core/less-add)

New module packages/core/src/less-add.ts with plan-based install logic:

Flow: Resolve → Validate → Plan → Review → Apply

Dry Run First

less add @scope/package --dry-run

Prints the full plan without changing any files:

  • Package source and version
  • Compatibility tier
  • Tags to register
  • File mutations (add/modify/remove)
  • Warnings and rejected tags

Validation Gate

Before any file mutation, the v0.18.1 validator is run. If the manifest
fails validation, the add stops immediately with zero file changes.

File Mutations Generated

For a valid SSR-capable package, the plan includes:

File Change
vite.config.ts Add to packageIslands array
vite.config.ts Add to ssr.noExternal list (SSR-capable only)
src/less-imports.ts Create/update client registration

Compatibility-Aware Behavior

Tier Behavior
ssr-capable Full setup: packageIslands + noExternal + registration
client-only packageIslands + registration only (no noExternal)
rejected No mutations — validation error stops the flow

Rollback Safety

If any write fails, the plan prints:

  • Which files were changed
  • Recovery command or manual rollback instructions
  • Does not continue to build

New Public API

Added to @lessjs/core:

Types:

  • AddPlan — full install plan with tags, mutations, status
  • AddTagEntry — per-tag entry in the install plan
  • FileMutation — single file change descriptor
  • PackageSource — local / jsr / npm

Functions:

  • generateAddPlan(options) — generate an install plan for a package

Exports:

  • @lessjs/core/less-add — install flow module
  • @lessjs/core/cli/less-add — CLI entry point

Verification

  • less add ./fixtures/ssr-capable --dry-run changes no files
  • less add ./fixtures/client-only --dry-run reports client-only outcome
  • invalid package fails before file writes
  • real install updates expected files only
  • rerunning install is idempotent (same input → same plan)
  • uninstall/manual rollback instructions are printed when needed
  • deno task fmt && deno task lint && deno task typecheck
  • deno task test (673 tests, 14 new)
  • deno task build

Breaking Changes

None. v0.18.2 adds new API surface without modifying existing interfaces.

  • New optional exports: generateAddPlan
  • New optional subpath exports: @lessjs/core/less-add, @lessjs/core/cli/less-add
  • No behavior changes to existing code

Migration Guide

For users: No action needed. v0.18.2 is a drop-in replacement for v0.18.1.

To add a package:

# First, check what would happen
deno run -A jsr:@lessjs/core/cli/less-add @scope/package --dry-run

# Then apply
deno run -A jsr:@lessjs/core/cli/less-add @scope/package

Next Steps

With v0.18.2 complete, the project can now proceed to:

  • v0.18.3: DOM simulation experiment for client-only components
  • See docs/sop/v0.18.3-dom-simulation-experiment.md

Diff Summary

git diff --stat v0.18.1..v0.18.2

packages/core/__tests__/less-add.test.ts (new, 193 lines)
packages/core/deno.json (2 lines changed)
packages/core/src/cli/less-add.ts (new, 123 lines)
packages/core/src/index.ts (10 lines changed)
packages/core/src/less-add.ts (new, 253 lines)

Stats:

  • 3 new files
  • 2 modified files
  • 14 new tests (673 total)
  • +581 / -0 lines
Assets 2
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