如何解决Javascript-使用多个变量作为对象属性
object.js
ob_start();
imagejpeg( $img,NULL,100 );
imagedestroy( $img );
$i = ob_get_clean();
echo "<img src='data:image/jpeg;base64," . base64_encode( $i )."'>";
结果1：
当@Component({
selector: 'my-component'
})
export class LinkInitComponent implements OnInit {
public linkKind: 'phoneLink' | 'emailLink' | 'routerLink' | 'simpleLink' | 'simpleText';
ngOnInit(): void {
this.linkKind = this.initLinlType();
}
private initLinlType(): 'phoneLink' | 'emailLink' | 'routerLink' | 'simpleLink' | 'simpleText' {
return 'simpleText'
}
}
为var a = "level_2";
var b = "level_3";
var c;
const nums = [1,2,3,4];
const num_1 = nums[Math.floor(Math.random() * nums.length)];
const num_2 = nums[Math.floor(Math.random() * nums.length)];
console.log({ num_1,num_2 });
if (num_1 <= num_2) {
c = [a];
} else {
c = [a][b];
}
/**
* Lets say I make a database call,the result is from a promise I use '.then()'
* eg:
* ...
* .then(level_1 => {
* let final;
* final = level_1[c]
* res.statusCode(200).json({ final })
* })...
*
* This is what I'm trying to achieve where I can determine the object property
* how deep in the object I would like to go before I get the object.*/
const level_1 = {
level_2: {
level_3: "level_3",level_4: "level_4",level_5: {
level_6: "level_6",},};
console.log("\nPrint 1:\n",level_1[a]);
console.log("\nPrint 2:\n",level_1[a][b]);
console.log("\nPrint 3:\n",level_1[c]);
c结果2：
如果只有[a][b]，则$ node object.js
{ num_1: 4,num_2: 1 }
Print 1:
{
level_3: 'level_3',level_4: 'level_4',level_5: { level_6: 'level_6' }
}
Print 2:
level_3
Print 3:
undefined
会很好用
c如何让[a]工作？如您所见，$ node object.js
{ num_1: 2,num_2: 3 }
Print 1:
{
level_3: 'level_3',level_5: { level_6: 'level_6' }
}
Print 2:
level_3
Print 3:
{
level_3: 'level_3',level_5: { level_6: 'level_6' }
}
为c返回了undefined，这已经困扰了我一段时间，如果有人可以帮助我，它将使我的代码非常有效。
解决方法
如果您希望能够合并属性，请使用属性数组，或通过.连接所有属性。然后，要获取嵌套的值，请使用Accessing nested JavaScript objects and arays by string path中的方法之一：
const level_1 = {
level_2: {
level_3: "level_3",level_4: "level_4",level_5: {
level_6: "level_6",},};
var a = "level_2";
var b = "level_3";
const c = [a,b];
const getNested = (obj,props) => props.reduce((a,prop) => a[prop],obj);
console.log(level_1[a]);
console.log(level_1[a][b]);
console.log(getNested(level_1,c));
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