Function memoize

test/fixtures/snapshot/typescript.js:1923–1932

(callback)

    }
    ts.notImplemented = notImplemented;
    function memoize(callback) {
        var value;
        return function () {
            if (callback) {
                value = callback();
                callback = undefined;
            }
            return value;
        };
    }
    ts.memoize = memoize;
    /** A version of `memoize` that supports a single primitive argument */
    function memoizeOne(callback) {