feat: add support for resize observer bindings

[TheCymaera]

Implements ResizeObserver bindings: #5524 (comment)
Continuation of: #5963
Related to #7583

<div bind:contentRect|contentBoxSize|borderBoxSize|devicePixelContentBoxSize>

I'm not familiar with the codebase so I'm not sure if this is the intended way to implement special bindings.

[TheCymaera]

I made a different pull request earlier using resize observers for the old dimension bindings.

I removed them as I was told that it would cause inconsistent behaviour between browsers.

With your permission, I'd like to re-implement it behind a compiler option, as the old bindings are easier to use.

resizeDetection: "iframe"|"resizeObserver"

[TheCymaera]

Hi all. I need some advice on how to fix this error. It is happening during node ./generate-type-definitions.js and is being caused by references to the ResizeObserver types. I was able to suppress it using the following but I need a way to fix it properly.

type ResizeObserverEntry = any;
type ResizeObserverOptions = any;
type ResizeObserver = any;
declare const ResizeObserver: any;

I tried changing the TSConfig version to ES2020 with no luck. I'm also not getting any type errors in VSCode.

Should I just copy the ResizeObserver type definitions from lib.dom.d.ts? That way we don't need to change lib versions.

[dummdidumm]

What's the error exactly? I would be ok to slap a // @ts-expect-error <explanation why> comment above it if that fixes it

[TheCymaera]

What's the error exactly? I would be ok to slap a // @ts-expect-error <explanation why> comment above it if that fixes it

Adding ts-expect-error prints Unused 'ts-expect-error' directive.
Adding ts-ignore or ts-nocheck doesn't fix it either.
This isn't a normal type error.

My above solution works and is probably fine since the observer is only used internally.

Error

> svelte@3.53.1 tsd
> node ./generate-type-definitions.js

node:child_process:891
    throw err;
    ^

Error: Command failed: tsc -p src/compiler --emitDeclarationOnly && tsc -p src/runtime --emitDeclarationOnly
    at checkExecSyncError (node:child_process:817:11)
    at execSync (node:child_process:888:15)
    at Object.<anonymous> (/Users/morgan/Desktop/svelte/generate-type-definitions.js:6:1)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Module._load (node:internal/modules/cjs/loader:827:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:77:12)
    at node:internal/main/run_main_module:17:47 {
  status: 1,
  signal: null,
  output: [
    null,
    Buffer(105) [Uint8Array] [
      115, 114,  99,  47, 114, 117, 110, 116, 105, 109, 101,  47,
      105, 110, 116, 101, 114, 110,  97, 108,  47,  82, 101, 115,
      105, 122, 101,  79,  98, 115, 101, 114, 118, 101, 114,  83,
      105, 110, 103, 108, 101, 116, 111, 110,  46, 116, 115,  40,
       50,  51,  44,  50,  50,  41,  58,  32, 101, 114, 114, 111,
      114,  32,  84,  83,  50,  51,  48,  52,  58,  32,  67,  97,
      110, 110, 111, 116,  32, 102, 105, 110, 100,  32, 110,  97,
      109, 101,  32,  39,  82, 101, 115, 105, 122, 101,  79,  98,
      115, 101, 114, 118,
      ... 5 more items
    ],
    Buffer(0) [Uint8Array] []
  ],
  pid: 70590,
  stdout: Buffer(105) [Uint8Array] [
    115, 114,  99,  47, 114, 117, 110, 116, 105, 109, 101,  47,
    105, 110, 116, 101, 114, 110,  97, 108,  47,  82, 101, 115,
    105, 122, 101,  79,  98, 115, 101, 114, 118, 101, 114,  83,
    105, 110, 103, 108, 101, 116, 111, 110,  46, 116, 115,  40,
     50,  51,  44,  50,  50,  41,  58,  32, 101, 114, 114, 111,
    114,  32,  84,  83,  50,  51,  48,  52,  58,  32,  67,  97,
    110, 110, 111, 116,  32, 102, 105, 110, 100,  32, 110,  97,
    109, 101,  32,  39,  82, 101, 115, 105, 122, 101,  79,  98,
    115, 101, 114, 118,
    ... 5 more items
  ],
  stderr: Buffer(0) [Uint8Array] []
}

Node.js v18.0.0
node:child_process:891
    throw err;

[vercel]

@dummdidumm is attempting to deploy a commit to the Svelte Team on Vercel.

A member of the Team first needs to authorize it.

[Conduitry]

This has been released in 3.59.0. Thank you!

[philholden]

Good to have this feature as it should be more performant but feels less ergonomic than clientWidth for getting hold of width:

Old:

<script>
  let clientWidth
</script>
<div bind:clientWidth>Width: {clientWidth}</div>

New (pretty hard to remember):

<script>
  let borderBoxSize;
  let width;
  $: width = borderBoxSize && borderBoxSize[borderBoxSize.length-1]?.inlineSize;
</script>
<div bind:borderBoxSize>Width {width}</div>

Any chance of some shorthand that removes this boilerplate e.g.:

<script>
  let borderBoxInlineSize;
</script>
<div bind:borderBoxInlineSize>Width: {borderBoxInlineSize}</div>

[aradalvand]

Is this documented? It looks like it isn't.
I wouldn't have known this feature existed had I not stumbled into this PR, it should be mentioned in the docs.

[hackape]

@aradalvand Good catch! Would you like to submit a PR to supplement the docs?