Apply a consistent, tool-friendly coding style to reduce formatting churn and improve readability.

Rules

• Keep diffs stable: Don’t apply formatting-only changes to existing tests/cases unless the PR’s purpose is explicitly formatting coverage. Revert incidental alignment/whitespace changes; add new focused cases instead.
• Respect formatter/tool expectations: e.g., avoid adding/removing whitespace in import groups if your tooling depends on it.
• String/concatenation consistency: build class/name strings consistently (no mixed whitespace prefixes like ` ‘ ‘ + a sometimes vs a + ‘ ‘` other times). Prefer a single consistent pattern.
• Use clearer JS constructs:
  • Prefer template literals/backticks for readability when composing multi-line strings or larger literals.
  • Use === / !== everywhere (avoid ==).
  • Prefer early returns to simplify nested conditionals.
  • Avoid magic numbers in new code; use named constants if values affect layout/logic.

Example (test string readability + stable diffs)

it('should parse bidirectional arrow', async () => {
  const str = `sequenceDiagram\nAlice-><Bob:Hello Bob, how are you?`;
  await mermaidAPI.parse(str);
  const messages = diagram.db.getMessages();
  expect(messages).toHaveLength(1);
});

Example (avoid magic numbers)

const TODAY_LINE_WIDTH = 30;
line.attr('y2', conf.titleTopMargin + TODAY_LINE_WIDTH);

Use this checklist when preparing commits: if a change is purely formatting, isolate it (or revert it) and keep PR intent behavior-focused.