Function isStringTypeExpression

scripts/extractFormFields.ts:38–56

* Determines whether a TypeScript expression resolves to a plain string value. * Only string literals and t() calls with a string literal argument are considered * string-typed; anything else (variables, conditionals, JSX elements, other calls) * causes the caller to bail out.

(expr: ts.Expression)

 * causes the caller to bail out.
 */
function isStringTypeExpression(expr: ts.Expression): boolean {
  // 'Name' or "Name"
  if (ts.isStringLiteral(expr)) {
    return true;
  }

  // t('Name') — the i18n translation helper
  if (
    ts.isCallExpression(expr) &&
    ts.isIdentifier(expr.expression) &&
    expr.expression.text === 't' &&
    expr.arguments.length > 0 &&
    ts.isStringLiteral(expr.arguments[0]!)
  ) {
    return true;
  }

  return false;
}

class FormFieldExtractor {
  private program: ts.Program;