Function isFunctionObject

src/math-json/utils.ts:55–66

(
  expr: MathJsonExpression | null
)

}

export function isFunctionObject(
  expr: MathJsonExpression | null
): expr is MathJsonFunctionObject {
  return (
    expr !== null &&
    typeof expr === 'object' &&
    'fn' in expr &&
    Array.isArray(expr.fn) &&
    expr.fn.length > 0 &&
    typeof expr.fn[0] === 'string'
  );
}

export function isExpressionObject(
  expr: MathJsonExpression | null