[英]Javascript loop through array of objects
我試圖遍歷一個數組,它一直說length
為0
數組的屏幕截圖:
我嘗試過for(key in results)...
和for( var i = 0; i < length...
但是在循環中都沒有運行任何東西: console.log(results[i]); // Or key if it's a key in loop
我確定這是一個菜鳥錯誤,有人可以發現嗎?
我正在使用的代碼:
var store = new Lawnchair({name: 'testing'}, function (store) {
// Create an object
var me = {key: 'Jordy', age: 19, date_of_birth: "1233-09-06"};
var mee = {key: 'dude', age: 17, date_of_birth: "2222-09-06"};
var meee = {key: 'gast', age: 8, date_of_birth: "5555-09-06"};
// Save it
store.save(me);
store.save(mee);
store.save(meee);
// Access it later... Yes even after a page refresh!
store.where('record.age < 20', function (records) {
var html = "";
var list = document.getElementById('people');
// for (var i = 0; i < records.length; i++) {
// var record = records[i];
// html += "<li>" + record.key + " is " + record.age + " years old and was born on " + record.date_of_birth + "</li>";
// }
for(var key in records){
console.log("SD");
}
console.log(records);
list.innerHTML = html;
});
});
當我在上方看到console.log(records)
,結果是屏幕截圖。 當我遍歷它時,什么都沒有發生,因為records.length === 0
編輯:
store.where('record.age < 20', function(records){
console.log(records); // Array with property length 3
console.log(records.length); // 0
});
第一個console.log
顯示帶有records.length === 3
的數組,但是第二個console.log
顯示0
。 怎么樣?
如果不提供代碼,很難說出您是否犯了菜鳥錯誤! 我看到您正在使用長度而不是arrayName.length? 我不知道您的陣列名稱...
for (var i = 0; i < array.length;i++){
//logic here
};
要迭代數組並產生副作用,請使用https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach
例如
[1,2,3,4].forEach(num => console.log(num));
另一方面,如果您需要過濾或變換數組,請考慮使用過濾器,映射或縮小。 https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Array
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