t.isLiteral()

function isLiteral(node, opts) {
    if (!node) return false;
    const nodeType = node.type;

    if ("StringLiteral" === nodeType ||
        "NumericLiteral" === nodeType ||
        "NullLiteral" === nodeType ||
        "BooleanLiteral" === nodeType ||
        "RegExpLiteral" === nodeType ||
        "TemplateLiteral" === nodeType ||
        "BigIntLiteral" === nodeType ||
        "DecimalLiteral" === nodeType ||
        nodeType === "Placeholder" && "StringLiteral" === node.expectedNode) {
        if (typeof opts === "undefined") {
            return true;
        } else {
            return (0, _shallowEqual.default)(node, opts);
        }
    }

    return false;
}