Bootstrap

浏览器彩色日志打印器

原文链接

博客

github

这两天队友在做一个uni-app项目,交接的时候发现他是用浏览器调试的,而我写的代码用了log4js,浏览器不能使用这个npm包,于是我决定给他写一个浏览器彩色日志打印器。

核心原理

是利用浏览器的console.log方法,通过css样式来实现彩色打印。

eg:

console.log(
    "%c%s",
    "color:#17a8cd;background-color:#d4f5ff;", 
    "这是一条debug日志"
);

代码

class Logger {
    /**
     * @param {string} level
     */
    set level(level) {
        if (["debug", "info", "warn", "error"].indexOf(level) == -1) {
            throw new Error("level must be debug | info | warn | error");
        }
        this._level = level;
        this._levelnum = ["debug", "info", "warn", "error"].indexOf(level);
    }
    constructor(name = "log", level = "debug") {
        this._level = "debug"; // debug | info | warn | error
        this._levelnum = 0;
        this._name = name;
        this.level = level;
        this.color = this.stringToColor(name);
    }
    debug(...msg) {
        if (this._levelnum > 0)
            return;
        let css = "color:#17a8cd;background-color:#d4f5ff;";
        console.log("%c%s", css, `[${this.getTimestamp()}] [DEBUG] [${this._name}] - `, ...msg);
    }
    info(...msg) {
        if (this._levelnum > 1)
            return;
        let css = "color:#008a15;background-color:#e6ffe9;";
        console.log("%c%s", css, `[${this.getTimestamp()}] [INFO] [${this._name}] - `, ...msg);
    }
    warn(...msg) {
        if (this._levelnum > 2)
            return;
        let css = "color:#e88f21;background-color:#fffbe6;";
        console.log("%c%s", css, `[${this.getTimestamp()}] [WARN] [${this._name}] - `, ...msg);
    }
    error(...msg) {
        if (this._levelnum > 3)
            return;
        let css = "color:#ff0000;background-color:#fff0f0;";
        console.log("%c%s", css, `[${this.getTimestamp()}] [ERROR] [${this._name}] - `, ...msg);
    }
    getTimestamp() {
        return new Date(new Date().valueOf() + 1000 * 60 * 60 * 8).toISOString();
    }
    log(...msg) {
        console.log("%c%s", `color:${this.color};`, `[${this.getTimestamp()}] [LOG] [${this._name}] - `, ...msg);
    }
    // 将任意字符串转换为颜色值
    stringToColor(str) {
        var hash = 0;
        for (var i = 0; i < str.length; i++) {
            hash = str.charCodeAt(i) + ((hash << 5) - hash);
        }
        var color = '#';
        for (var i = 0; i < 3; i++) {
            var value = (hash >> (i * 8)) & 0xFF;
            color += ('00' + value.toString(16)).substr(-2);
        }
        return color;
    }
}

have a try

你可以按 F12 打开浏览器控制台试一下

let log = new Logger("test", "debug");
log.debug("这是一条debug日志");
log.info("这是一条info日志");
log.warn("这是一条warn日志");
log.error("这是一条error日志");
log.log("这是一条log日志,颜色是根据名称自动生成的");

更新

2023-9-10

将项目发布为npm包,项目地址:opchatjs-webLogger

参考资料

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