Function stringValue

src/math-json/utils.ts:98–108

(
  expr: MathJsonExpression | null | undefined
)

 * **U+0027 APOSTROPHE** : **`'`** or an object literal with a `str` key.
 */
export function stringValue(
  expr: MathJsonExpression | null | undefined
): string | null {
  if (expr === null || expr === undefined) return null;
  if (typeof expr === 'object' && 'str' in expr) return expr.str;
  if (typeof expr !== 'string') return null;
  if (expr.length >= 2 && expr.at(0) === "'" && expr.at(-1) === "'")
    return expr.substring(1, expr.length - 1);
  if (matchesNumber(expr) || matchesSymbol(expr)) return null;
  return expr;
}

export function stripText(
  expr: MathJsonExpression | null | undefined