Question

我正在尝试将一个vanilla ES5闭合重写为ES2015 Class。该代码会覆盖window.onerror函数，并充当用于记录目的的全局错误处理程序方法。

我的旧代码看起来像这样。我想知道如何在ES2015中重写它。我如何覆盖Window.onerror？

    (function() {

        window.onerror = function(errorMessage, url, line) {
            try {
                if (typeof(url) === "undefined") {
                    url = "";
                }
                if (typeof(line) === "undefined") {
                    line = "";
                }

                // Avoid error message being too long...
                if (errorMessage.length > 300) {
                    errorMessage = errorMessage.slice(0,300) + "...";
                }

                errorMessage = errorMessage.replace(/&/g, "%26").replace(/ /g, "+");
                url = url;
                line = line;
                var parentUrl = encodeURIComponent(document.location.href);

                // Set error details
                var parameters = "error_message=" + errorMessage +
                                 "&url=" + url +
                                 "&line=" + line +
                                 "&parent_url=" + parentUrl;

                // Set path to log target
                var logUrl = "xxx";

                // Set error details as image parameters
                new Image().src = logUrl + '?' + parameters;
            } catch (e) {}
        };

    }());

编辑！现在我正在尝试在JS类中重写它。所以我想我必须扩展Window类或类似的东西（我有Java背景）。但是，据我所知，Window不是一个班级。这就是我到目前为止所拥有的。

所以我需要帮助来覆盖用ES2015编写的window.onerror函数！

export const Logging = new class {

    constructor() {
        // todo
    }

    onerror(errorMessage, url, line) {
        try {
            if (typeof(url) === "undefined") {
                url = "";
            }
            if (typeof(line) === "undefined") {
                line = "";
            }

            // truncate error message if necessary
            if (errorMessage.length > 300) {
                errorMessage = errorMessage.slice(0,300) + "...";
            }

            // URI encoding
            errorMessage = errorMessage.replace(/&/g, "%26").replace(/ /g, "+");
            url = url;
            line = line;
            var parentUrl = encodeURIComponent(document.location.href);

            // set error details
            var parameters = "error_message=" + errorMessage +
                "&url=" + url +
                "&line=" + line +
                "&parent_url=" + parentUrl;

            // Set path to log target
            var logUrl = "xxx";

            // set error details as image parameters
            var img = new Image().src = logUrl + '?' + parameters;

            console.log(img);
        }
        catch (e) {}
    }

}

/* ------------------------------------------------------------------------------------------------------------ */

export default Logging;

Answer 1

这里唯一有用的是参数默认值。我改变的其他一切都已经在ES5中被误认为了。

window.onerror = function(errorMessage, url="", line="") {
    try {
        // Avoid error message being too long...
        if (errorMessage.length > 303) {
            errorMessage = errorMessage.slice(0,300) + "...";
        }
        var parentUrl = document.location.href;

        // Set error details
        var parameters = "error_message=" + encodeURIComponent(errorMessage).replace(/%20/g, "+") +
                         "&url=" + encodeURIComponent(url) +
                         "&line=" + encodeURIComponent(line) +
                         "&parent_url=" + encodeURIComponent(parentUrl);

        // Set path to log target
        var logUrl = "xxx";

        // Set error details as image parameters
        new Image().src = logUrl + '?' + parameters;
    } catch (e) {}
};

如何在ES2015中覆盖Window上的方法

1 个答案: