这个打字稿 forEach 片段有什么作用？

Question

When I am about to type forEach() in a typescript file the Visual Studio Code editor offers me this snippet

and pastes in the following:

    let foo: any;
    
    // something gets assigned to foo...

    foo.array.forEach(element => {
        
    });

Why does it insert the array property and what is it? In what scenario is this snippet intended to be used?

UPDATE 2020: I see the foreach snippet that adds "array" is no longer offered by VSCode in this situation. I guess I wan't the only person who found it confusing.

Answer 1

For that snippet you don't use yourArray.forEa... and then select the snippet.

You just use it directly as forEa... and when you click on it the full snippet gets created with array placeholder which you can immediately replace with the name of your array.

So what you did is you put your array at the beggining which is extra and not needed, and on that you appended a full snippet, which already has array placeholder.

---

PS I think it would be more intuitive if the snippet was made the way you try to use it. This happens to me every time, so I have to delete the excessive array. that gets created. But this is just my opinion.

Answer 2

In Visual Studio Code editor you can also add your own snippets, that will be available as the others, by following File->Preferences(Code > Preferences on macOS)->User Snippets: Type in typescript.json (for this case) in input : Paste your snippet (if you would like to use it without automatically pasted property array ), and save:

"forEach - my": {
    "prefix": "forEach",
    "body": [
        "forEach(element => {",
        "});" 
    ],
    "description": "My forEach"
}

forEach - my is the snippet name.

prefix is how this snippet is selected from IntelliSense and tab completion.

body is the content and either a single string or an array of strings of which each element will be inserted as separate line.

description is the description used in the IntelliSense drop down.

More is here: https://code.visualstudio.com/docs/editor/userdefinedsnippets