javascript - 我怎样才能摆脱在函数之前放置 "new"

Question

我想知道如何才能摆脱在函数之前放置“new”的情况，例如:

new functionToDo("thingsToDo").iGotYouBruh("Halo Humans");

有没有一种可行的方法可以在没有"new"的情况下做到这一点？

这是我尝试在没有“new”的情况下使用的代码:

function local (title) {
    var storeTitle = title;
    this.addL = function(lString) {
        var storeText = lString;
        localStorage.setItem(storeTitle, storeText);
        console.info("Locally stored " + storeTitle.toUpperCase() + " with " + storeText.substring(0, 10) + "... As text.");
    };
    this.removeL = function() {
        localStorage.removeItem(storeTitle);
        console.info("Locally removed " + storeTitle + ".");
    };
    this.getL = function () {
        localStorage.getItem(storeTitle);
        console.info("Locally got string of " + storeTitle + ": " + localStorage.getItem(storeTitle));
    };
};

这是我必须执行的操作才能调用该函数:

new local("storedElement").getL();

Answer 1

这可以通过检查 this 是否是函数本身的实例并返回一个新实例来实现:

function local (title) {
    if (!(this instanceof local)) {
        return new local(title);
    }

    var storeTitle = title;
    this.addL = function(lString) {
        var storeText = lString;
        localStorage.setItem(storeTitle, storeText);
        console.info("Locally stored " + storeTitle.toUpperCase() + " with " + storeText.substring(0, 10) + "... As text.");
    };
    this.removeL = function() {
        localStorage.removeItem(storeTitle);
        console.info("Locally removed " + storeTitle + ".");
    };
    this.getL = function () {
        localStorage.getItem(storeTitle);
        console.info("Locally got string of " + storeTitle + ": " + localStorage.getItem(storeTitle));
    };
};