[js] changes to allow Float16Array if any polyfill is available (#19305)

### Description

This change adds only necessary code to enable ort-web works with any
Float16Array polyfill. Unlike #19302, in this PR, ort-web does not
include any specific polyfill; instead, it's user's choice for how to
use a polyfill.

ORT-web uses Float16Array if it's available; otherwise, fallback to use
Uint16Array.

```js
// case 1: user does not use polyfill:
import * as ort from 'onnxruntime-web';

const myF16Data = new Uint16Array(...);  // need to use Uint16Array
const myF16tensor = new ort.Tensor('float16', myF16Data, dims);
```

```js
// case 2: user use polyfill:
import * as ort from 'onnxruntime-web';
import {
  Float16Array, isFloat16Array, isTypedArray,
  getFloat16, setFloat16,
  f16round,
} from "@petamoriken/float16";
globalThis.Float16Array = Float16Array;  // ort-web will pick the global Float16Array

const myF16Data = new Float16Array(...);  // Use the polyfilled Float16Array type
const myF16tensor = new ort.Tensor('float16', myF16Data, dims);
```

js/common/lib/tensor-impl-type-mapping.ts

@@ -14,7 +14,6 @@ export const NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP = new Map<string, SupportedTy
   ['uint8', Uint8Array],
   ['int8', Int8Array],
   ['uint16', Uint16Array],
-  ['float16', Uint16Array],
   ['int16', Int16Array],
   ['int32', Int32Array],
   ['bool', Uint8Array],
@@ -34,16 +33,22 @@ export const NUMERIC_TENSOR_TYPEDARRAY_TO_TYPE_MAP = new Map<SupportedTypedArray
   [Uint32Array, 'uint32'],
 ]);
 
-// the following code allows delaying execution of BigInt checking. This allows lazy initialization for
-// NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP and NUMERIC_TENSOR_TYPEDARRAY_TO_TYPE_MAP, which allows BigInt polyfill
-// if available.
-let isBigIntChecked = false;
-export const checkBigInt = () => {
-  if (!isBigIntChecked) {
-    isBigIntChecked = true;
-    const isBigInt64ArrayAvailable = typeof BigInt64Array !== 'undefined' && typeof BigInt64Array.from === 'function';
-    const isBigUint64ArrayAvailable =
-        typeof BigUint64Array !== 'undefined' && typeof BigUint64Array.from === 'function';
+// a dummy type declaration for Float16Array in case any polyfill is available.
+declare global {
+  // eslint-disable-next-line @typescript-eslint/naming-convention, @typescript-eslint/no-explicit-any
+  const Float16Array: any;
+}
+
+// the following code allows delaying execution of BigInt/Float16Array checking. This allows lazy initialization for
+// NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP and NUMERIC_TENSOR_TYPEDARRAY_TO_TYPE_MAP, which allows BigInt/Float16Array
+// polyfill if available.
+let isTypedArrayChecked = false;
+export const checkTypedArray = () => {
+  if (!isTypedArrayChecked) {
+    isTypedArrayChecked = true;
+    const isBigInt64ArrayAvailable = typeof BigInt64Array !== 'undefined' && BigInt64Array.from;
+    const isBigUint64ArrayAvailable = typeof BigUint64Array !== 'undefined' && BigUint64Array.from;
+    const isFloat16ArrayAvailable = typeof Float16Array !== 'undefined' && Float16Array.from;
 
     if (isBigInt64ArrayAvailable) {
       NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP.set('int64', BigInt64Array);
@@ -53,5 +58,12 @@ export const checkBigInt = () => {
       NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP.set('uint64', BigUint64Array);
       NUMERIC_TENSOR_TYPEDARRAY_TO_TYPE_MAP.set(BigUint64Array, 'uint64');
     }
+    if (isFloat16ArrayAvailable) {
+      NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP.set('float16', Float16Array);
+      NUMERIC_TENSOR_TYPEDARRAY_TO_TYPE_MAP.set(Float16Array, 'float16');
+    } else {
+      // if Float16Array is not available, use 'Uint16Array' to store the data.
+      NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP.set('float16', Uint16Array);
+    }
   }
 };

js/common/lib/tensor-impl.ts

@@ -5,7 +5,7 @@ import {tensorToDataURL, tensorToImageData} from './tensor-conversion-impl.js';
 import {TensorToDataUrlOptions, TensorToImageDataOptions} from './tensor-conversion.js';
 import {tensorFromGpuBuffer, tensorFromImage, tensorFromPinnedBuffer, tensorFromTexture} from './tensor-factory-impl.js';
 import {CpuPinnedConstructorParameters, GpuBufferConstructorParameters, TensorFromGpuBufferOptions, TensorFromImageBitmapOptions, TensorFromImageDataOptions, TensorFromImageElementOptions, TensorFromTextureOptions, TensorFromUrlOptions, TextureConstructorParameters} from './tensor-factory.js';
-import {checkBigInt, NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP, NUMERIC_TENSOR_TYPEDARRAY_TO_TYPE_MAP, SupportedTypedArray, SupportedTypedArrayConstructors} from './tensor-impl-type-mapping.js';
+import {checkTypedArray, NUMERIC_TENSOR_TYPE_TO_TYPEDARRAY_MAP, NUMERIC_TENSOR_TYPEDARRAY_TO_TYPE_MAP, SupportedTypedArray, SupportedTypedArrayConstructors} from './tensor-impl-type-mapping.js';
 import {calculateSize, tensorReshape} from './tensor-utils-impl.js';
 import {Tensor as TensorInterface} from './tensor.js';
 
@@ -67,8 +67,8 @@ export class Tensor implements TensorInterface {
       arg0: TensorType|TensorDataType|readonly string[]|readonly boolean[]|CpuPinnedConstructorParameters|
       TextureConstructorParameters|GpuBufferConstructorParameters,
       arg1?: TensorDataType|readonly number[]|readonly string[]|readonly boolean[], arg2?: readonly number[]) {
-    // perform one-time check for BigInt support
-    checkBigInt();
+    // perform one-time check for BigInt/Float16Array support
+    checkTypedArray();
 
     let type: TensorType;
     let dims: readonly number[];
@@ -142,7 +142,9 @@ export class Tensor implements TensorInterface {
             throw new TypeError(`Unsupported tensor type: ${arg0}.`);
           }
           if (Array.isArray(arg1)) {
-            if (arg0 === 'float16') {
+            if (arg0 === 'float16' && typedArrayConstructor === Uint16Array) {
+              // When no Float16Array polyfill is used, we cannot create 'float16' tensor from number array.
+              //
               // Throw error here because when user try to use number array as data,
               // e.g. new Tensor('float16', [1, 2, 3, 4], dims)), it will actually call
               // Uint16Array.from(arg1) which generates wrong data.

js/web/lib/wasm/wasm-common.ts

@@ -3,6 +3,12 @@
 
 import {Tensor} from 'onnxruntime-common';
 
+// a dummy type declaration for Float16Array in case any polyfill is available.
+declare global {
+  // eslint-disable-next-line @typescript-eslint/naming-convention, @typescript-eslint/no-explicit-any
+  const Float16Array: any;
+}
+
 // This file includes common definitions. They do NOT have dependency on the WebAssembly instance.
 
 /**
@@ -117,7 +123,8 @@ export const tensorTypeToTypedArrayConstructor = (type: Tensor.Type): Float32Arr
     Uint8ArrayConstructor|Float64ArrayConstructor|Uint32ArrayConstructor|BigUint64ArrayConstructor => {
       switch (type) {
         case 'float16':
-          return Uint16Array;
+          // allow Float16Array polyfill.
+          return typeof Float16Array !== 'undefined' && Float16Array.from ? Float16Array : Uint16Array;
         case 'float32':
           return Float32Array;
         case 'uint8':