Reviewing LWC RTL

Run a structured right-to-left (RTL) internationalization compliance pass over a Lightning Web Component, producing a report of issues found and code-level fixes to bring the component into compliance with Salesforce RTL guidelines.

When to Use

• The user asks for an "RTL review", "i18n check", "RTL compliance pass", or "RTL audit" on a specific LWC.
• Preparing a component for release in RTL locales (Arabic, Hebrew, Farsi, Urdu).
• Investigating layout defects reported in RTL environments.
• Verifying SLDS class usage after a CSS refactor.

Do NOT use this skill for:

• Building new components (use experience-lwc-generate).
• Modifying SLDS classes themselves (use design-systems-slds-apply or design-systems-slds2-migrate).
• Accessibility or security review — run those as separate passes with the relevant tooling.
• Gating a fix behind a feature flag (apply feature-flag gating after fixes land).

Prerequisites

• Component path (LWC bundle under modules/…).
• Access to the component's HTML templates, JS/TS, and CSS.

Knowledge Base

The reference is the source of truth. Do not summarize from memory — open the reference, apply the guidelines, and cite the specific section you used in the report.

• RTL internationalization: RTL Expert

Workflow

Step 1 — Scope the review

Collect the component path and identify the files to review: .html, .js/.ts, .css, and any child components owned by the same team that are invoked from the target.

Note any existing feature-flag gates (e.g., Aura.org.rtlPhase1FixEnabled) — findings that require code changes must respect them.

Step 2 — Read the knowledge base

Read RTL Expert top-to-bottom before judging. It enumerates the physical-to-logical property mappings, bidirectional text handling patterns, and — critically — the SLDS constraints that override generic RTL advice.

Step 3 — CSS inspection

Run the deterministic scanner over every .css file in the bundle. The scanner matches CSS declarations only — never SLDS class names in HTML class="…" attributes (see Step 5). Inline style="…" attributes must be scanned separately (either by extracting them into a temp file or by inspecting the HTML by hand and applying the same rules).

"<skill_dir>/scripts/scan-rtl-css.sh" <cssFile1> [<cssFile2> ...]

Each output line has the shape <file>:<line>: <property>: <value> -> <logical-property>: <logical-value>. The scanner tokenizes declarations (splits on ; inside {…}) so minified multi-declaration lines produce one finding per physical declaration and selector names are never rewritten. Translate each line into a Step 6 bullet (<file>:<line> — <pattern> → <logical property> plus a one-sentence Fix). Empty output IS a valid result — record it as "No issues found." in the report.

Scanner-recognised patterns (kept in sync with the script's regex — do not add rules here without also updating scan-rtl-css.sh):

• left / right → inset-inline-start / inset-inline-end
• margin-left / margin-right → margin-inline-start / margin-inline-end
• padding-left / padding-right → padding-inline-start / padding-inline-end
• text-align: left / right → text-align: start / end
• border-left-* / border-right-* → border-inline-start-* / border-inline-end-*
• float: left / float: right → float: inline-start / float: inline-end (or remove and use flex/grid)
• transform: translateX(...) — flagged; sign-flip or use a logical alternative

border-radius with explicit corners is not scanned automatically — inspect corner shorthand by hand and translate to the logical corner variants.

Step 4 — HTML / JS inspection

Walk templates and JS for:

• Icon flipping hints — flag only icons with directional semantics that appear in plain HTML <img> / inline SVG / raw Unicode / background-image CSS. Do NOT flag <lightning-icon> in LWC templates (including directional utility names like utility:chevronright, utility:chevronleft, utility:back, utility:forward); lightning-icon renders through the Lightning icon service, which mirrors directional utility icons automatically in RTL locales. Treat it the same way you treat SLDS utility classes.
• dir attribute usage — confirm it's sourced from locale, not hardcoded.
• Keyboard arrow-key semantics — Left/Right arrow handlers should swap in RTL where navigation is directional (tab bars, sliders, tree expand/collapse).
• Directional Unicode controls — ensure user-generated text is not stripped of RLM/LRM markers when rendered.
• Inline style="…" with physical properties — same rules as Step 3.

Step 5 — SLDS constraints

SLDS class handling is the highest-priority RTL rule. When a rule below says "do NOT flag", that class must not appear as a finding in the report — not as an issue, not as a "fix", not as a rename suggestion.

1. SLDS utility classes with _left / _right suffixes are RTL-aware and MUST NOT be flagged. They already mirror automatically in RTL under the hood — this includes slds-text-align_right, slds-text-align_left, slds-m-left_*, slds-m-right_*, slds-p-left_*, slds-p-right_*, slds-float_left, slds-float_right, slds-border_left, slds-border_right, and the rest of the _left / _right utility family. Leave them exactly as written.
2. _start / _end variants of SLDS classes DO NOT EXIST. Never rename slds-*_right → slds-*_end or slds-*_left → slds-*_start. There is no such class; the rename would break the stylesheet. If you are tempted to "fix" an SLDS utility class by adding _start/_end, STOP — the correct action is to leave the class alone (see rule 1).
3. Never modify, rename, or remove any slds-* class. SLDS ships RTL-aware stylesheets; altering classes breaks the contract.
4. If custom CSS duplicates what an SLDS class already handles, the fix is removal — not conversion. Delete the redundant custom rule; leave the SLDS class alone. Do NOT convert the removed property to its logical equivalent, and do NOT offer removal + conversion as two alternatives; there is one fix, and it is deletion. Example: float: right in a .css file next to class="slds-button__icon_right" in the template — delete the entire .custom-icon { float: right } rule. Do not "also suggest float: inline-end" — that would be wrong; the SLDS class already handles placement.
5. If an SLDS class has an RTL gap, add complementary custom CSS rather than altering the SLDS class.

Concrete negative example — a template with <span class="slds-text-align_right slds-m-right_small">…</span> alongside a custom padding-left: 4px in the component's CSS: the ONLY finding is the CSS padding-left (Step 3). The two slds-*_right classes are not findings and must not appear in the report.

Step 6 — Produce the report

Write <outputDir>/rtl-review.md in this exact shape (blank line after each ## heading; every summary sentence ends with a period):

## RTL

- <file>:<line> — <physical pattern> → <logical property / SLDS class>
  Fix: <one-sentence explanation>; applied: yes/no
- <file>:<line> — <physical pattern> → <logical property / SLDS class>
  Fix: <one-sentence explanation>; applied: yes/no

## Summary

- <n> issues found; <m> fixed; <k> deferred (with reason).
- <one-sentence overview of what was found and why the remaining items are correct or deferred>.
- Cite: RTL Expert — <section title>.

Populate the ## RTL bullets from the scan-rtl-css.sh output for CSS findings, and append hand-authored bullets in the same shape for the Step 4 HTML/JS findings. When there are no findings, emit the single bullet - No issues found. under ## RTL and a Summary that reports 0 issues found; 0 fixed; 0 deferred. plus a one-sentence overview and citation.

Step 7 — Apply fixes

For each accepted finding:

1. Edit the component files (CSS, HTML, JS/TS) to apply the fix.
2. Preserve existing correct behavior and existing feature-flag gates. If a gate is already configured (e.g., Aura.org.rtlPhase1FixEnabled), leave it untouched. Only when the caller has explicitly required a phased rollout for a new fix, wrap that fix behind a feature flag; otherwise apply the fix directly.
3. Do NOT remove or rename SLDS classes.
4. Do NOT silently delete old code — preserve the original path where a gate is required.

Step 8 — Verify

• Re-run the review against the updated files; every fixed finding must no longer appear.
• Run Jest tests and any component-level RTL visual tests.

Cross-References

• Related skills:
  • design-systems-slds-apply — for SLDS class-level changes beyond custom CSS cleanup.
  • design-systems-slds2-migrate — when RTL cleanup surfaces classes that need SLDS2 migration first.
  • experience-lwc-generate — when the review surfaces a need to regenerate the component rather than patch it.
  • Accessibility (WCAG 2.2) and security (LWS + Product Security) reviews are separate passes — run them with the appropriate tooling for each, not this skill.
  • Feature-flag gating is out of scope for this skill; apply it separately only when the caller has explicitly required a phased rollout (see Step 7).

Verification

• All RTL rules are green on the updated component (re-run scripts/scan-rtl-css.sh against every CSS file in the bundle — it must return empty for every fully-applied finding).
• No SLDS class was modified, renamed, or removed.
• Every finding has either been applied or has an explicit deferred note with a reason.
• The rtl-review.md matches the two-section shape defined in Step 6 (blank line after each ##; period-terminated summary sentences).