object generic

Array

Array

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// 简写形式
const arr:string[] = ["foo"];
const arr1:Array<string> = ["foo"];

ReadonlyArray

not changed

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const arr: ReadonlyArray<string> = [];

Tuple

No changed length and type

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let arr1: StringorNumber = ["foo", 1];

arr1[2] = 1; // error 
const arr1Index2 = arr1[2];
arr1.push("foo2");

Destruture Tuple

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function doSomething(stringHash: [string, number]) {
  const [inputString, hash] = stringHash;
  console.log(inputString);
  console.log(hash);
}

Optional tuple elements

Rest elements

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function readButtonInput(...args: [string, number, ...boolean[]]) {
  const [name, version, ...input] = args;
}
readButtonInput()

Readonly Tuple

no changed 

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function doSomething(pair: readonly [string, number]) {
  pair[0] = "hello!";
	// ^__ Cannot assign to '0' because it is a read-only property.
}

越界元素