解决遍历时Array.indexOf产生的性能问题_javascript技巧

Ext.applyIf(Array.prototype, {
/**
* Checks whether or not the specified object exists in the array.
* @param {Object} o The object to check for
* @param {Number} from (Optional) The index at which to begin the search
* @return {Number} The index of o in the array (or -1 if it is not found)
*/
indexOf : function(o, from){
var len = this.length;
from = from || 0;
from += (from for (; from if(this[from] === o){
return from;
}
});
return -1;
}

var hostsIP = [];
Ext.each(_this.hosts,function(item){
hostsIP.push(item.ip);
});
Ext.each(txtHostsIP,function(ip){
if(hostsIP.indexOf(ip)===-1){//问题代码
var host = {
isAppend : true,//新增的主机
isAgentOk : false,
ip : ip
};
_this.hosts.push(
Ext.apply(host,_this.MAPPING_FIELDS)
);
isAppend = true;
}else{
errors.push('IP['+ip+']已存在');
}
});

var hostsIP = {};
Ext.each(_this.hosts,function(item){
hostsIP[item.ip]=item.ip;
});

Ext.each(txtHostsIP,function(ip){
if(!hostsIP.hasOwnProperty(ip)){
var host = {
isAppend : true,//新增的主机
isAgentOk : false,
ip : ip
};
_this.hosts.push(
Ext.apply(host,_this.MAPPING_FIELDS)
);
isAppend = true;
}else{
errors.push('IP['+ip+']已存在');
}
});