Question

使用underscorejs我可以过滤对象中的数据，但它不会保留它的键。有没有办法用钥匙取回物品

var data = {
  foo: 'fff',
  bar: 'sss',
  aaa: 'gggg'
}
console.info('returns array with keys:')

console.log(data)

var ret = _.filter(data, function(el, key) {
  if (key == 'foo' || el == 'sss') {
    return true
  }
})

console.info('keys are lost?')
console.log(ret)

这是小提琴：https://jsfiddle.net/7L7tmq7s/

Answer 1

使用过滤器完成了工作：

console.log(data)
var filtered = {};
var ret = _.each(data, function(el, key) {
  if ((key == 'foo' || el == 'sss')) {
    filtered[key] = el;
  }
})

console.info('keys are not lost?')
console.log(filtered)

工作代码here

Answer 2

这样的事情怎么样（下划线在这里有点没用）？

var canvas = document.getElementById("signatureCanvas");
    if (canvas != null) {
        var ctx = canvas.getContext("2d");
        ctx.font = "12px sans-serif";
        ctx.fillStyle = "black";
        ctx.textAlign = "center";
        ctx.fillText("Signature", canvas.width / 2, canvas.height / 2);
    }

javascript对象过滤器 - 不返回关联键

2 个答案: