标签 js 下的文章

绍数组包对象格式 对应key相加

let arr = [{"ct":"1","total":"2003","subcompanyid":"1","subcompanyname":"郑州(ZZ)"},{"ct":"2","total":"2004","subcompanyid":"2","subcompanyname":"广东(GDW)"},{"ct":"3","total":"2005","subcompanyid":"3","subcompanyname":"广西(GX)"},{"ct":"4","total":"2006","subcompanyid":"4","subcompanyname":"厦门(XM)"},{"ct":"5","total":"2007","subcompanyid":"5","subcompanyname":"浙江(ZJ)"}]
let result =arr.reduce(function(total, value, idx, ar){
    return {
        total: parseInt(total.total) + parseInt(value.total),
        ct: parseInt(total.ct) + parseInt(value.ct)
    }
})

console.log(result)
// {total: 10025, ct: 15}

如果想自定义返回数据（total）格式可以传入第二个参数

let result =arr.reduce(function(total, value, idx, ar){
    console.log("total:", total, "\r\nvalue:", value)
    return {
        t: parseInt(total.t) + parseInt(value.total),
        c: parseInt(total.c) + parseInt(value.ct)
    }
}, {t:0, c:0})


<html>
<head>
  <meta charset="utf-8">
  <title>通过filereader接口读取文件</title>
  <script type="text/javascript">
    function getBase64Image(img) {
        var canvas = document.createElement("canvas");
        canvas.width = img.width;
        canvas.height = img.height;
        var ctx = canvas.getContext("2d");
        ctx.drawImage(img, 0, 0, img.width, img.height);
        var dataURL = canvas.toDataURL("image/png");
        return dataURL
        // return dataURL.replace("data:image/png;base64,", "");
    }

    function main(src) {
        var img = document.createElement('img');
        img.src = src + '?v=' + Math.random();  //此处自己替换本地图片的地址
        img.crossOrigin= 'anonymous'
        img.onload =function() {
          debugger
            var data = getBase64Image(img);
            var img1 = document.createElement('img');
            img1.src = data;
            document.body.appendChild(img1);
            console.log(data);
        }
    }
    var url = 'http://domain/x.jpg';
    main(url)
</script>
</head>

<body>
</body>

</html>