underscore.js _.include [Collections]

Returns true if the value is present in the list, using === to test equality. UsesindexOf internally, if list is an Array.

检测值是否在列表中出现过，如果出现返回true

_.include([1, 2, 3], 3);
=> true

源码:

 _.include = _.contains = function(obj, target) {
    var found = false;
    if (obj == null) return found;
    if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
    found = any(obj, function(value) {
      return value === target;
    });
    return found;
  };