如何分離Typescript中的數組

Question

我正在用Angular2創建一個應用程序，並且我有一組派對。

const PARTIES: Party[] = [ 
    { id: 1, title: "Main Event", description: "The biggest, most extravagant event in the last 10,000,000 years." }, 
    { id: 2, title: "Secondary Event", description: "The not as biggest, less extravagant event in the last 10,000,000 years." }, 
    { id: 3, title: "Another Event", description: "N/A" }, 
    { id: 4, title: "Another Event", description: "N/A" }, 
    { id: 5, title: "Another Event", description: "N/A" }, 
    { id: 6, title: "Another Event", description: "N/A" }, 
    { id: 7, title: "Another Event", description: "N/A" }, 
    { id: 8, title: "Another Event", description: "N/A" }, 
    { id: 9, title: "Another Event", description: "N/A" }, 
    { id: 10, title: "Another Event", description: "N/A" } 
]; 

同時保留原始陣列，我想起來拆分此陣列分成的3

段在普通的舊的JavaScript，我會使用以下內容。

var chunk_size = 3; 
var arr = PARTIES; 
var groups = arr.map(function(e,i){ 
    return i%chunk_size===0 ? arr.slice(i,i+chunk_size) : null; 
}) 
.filter(function(e){ return e; }); 
PARTIES = groups 

但是，我正在使用TypeScript。是否有任何可能的方式來執行我想用TypeScript實現的目標？

Answer 1

你的JavaScript代碼：

var chunk_size = 3; 
var arr = PARTIES; 
var groups = arr.map(function(e,i){ 
    return i%chunk_size===0 ? arr.slice(i,i+chunk_size) : null; 
}) 
.filter(function(e){ return e; }); 
PARTIES = groups 

是不正確的。如果是這將是有效的打字稿和它只是工作，因爲JavaScript是打字稿https://basarat.gitbooks.io/typescript/content/docs/why-typescript.html :)

修復

以下是工作示例：

const PARTIES = [ 
    { id: 1, title: "Main Event", description: "The biggest, most extravagant event in the last 10,000,000 years." }, 
    { id: 2, title: "Secondary Event", description: "The not as biggest, less extravagant event in the last 10,000,000 years." }, 
    { id: 3, title: "Another Event", description: "N/A" }, 
    { id: 4, title: "Another Event", description: "N/A" }, 
    { id: 5, title: "Another Event", description: "N/A" }, 
    { id: 6, title: "Another Event", description: "N/A" }, 
    { id: 7, title: "Another Event", description: "N/A" }, 
    { id: 8, title: "Another Event", description: "N/A" }, 
    { id: 9, title: "Another Event", description: "N/A" }, 
    { id: 10, title: "Another Event", description: "N/A" } 
]; 

var chunk_size = 3; 
const groups = PARTIES.map(function(e,i){ 
    return i%chunk_size===0 ? PARTIES.slice(i,i+chunk_size) : null; 
}) 
.filter(x=>!!x) 

console.log(groups); 

的一些注意事項的修復：

• const不能被重新分配。所以你不能重新分配給各方
• 各方的類型（[]）是不一樣的類型groups（[][]），所以你不想來指派反正
• 不如在filter使用真實boolean代替truthy/falsy檢查。更多：https://basarat.gitbooks.io/typescript/content/docs/tips/truthy.html