Openlayers 3 检查crossorigin参数的所有（可见）图层，并根据其返回变量

在检查了地图的图层的crossOrigin属性（如果给定）后，我试图接收一个变量

事实上，我想设置变量printposs=true/false

只要一个可见层没有正确的交叉原点值，变量就应该变为可能=真，函数/foreach循环可以退出，返回值“外部”

这就是我的知识贫乏所得到的。但变量似乎总是保持最后处理层的值

JSFIDLE here：（我添加了浏览器控制台日志）

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}))

当然，您必须在循环交互开始时将变量设置为其初始值（

undefined

）。

map.getLayers().forEach(function (layer, idx, a) {
if (layer instanceof ol.layer.Group) {
    layer.getLayers().forEach(function (sublayer, jdx, b) {
        var origin = sublayer.getSource()['crossOrigin'];
        var visible = sublayer.getVisible();
        var title = sublayer.get('title');

        if (visible === true && origin == 'anonymous') {
        printposs=true;

        } else if (visible == false) {
            printposs = true;

        } else {
            printposs = false;

            //return printposs; can abort here as soon as one visible layer doesnt have Crossorigin
        }

        return printposs;
    });
    console.log('outer return:' + printposs + ' - It seems always the value of the last "processed" layer is returned')
}