Generic JsResult<R> in context.throw_ methods (#1734)

Previously when we had the `context.throw_` methods (like `context.thtrow_type_error()`) they were limited as to where we could call them, e.i. a function that returned `JsResult<JsValue>`. So we had to call the `context.construct_` methods with an explicit `Err()` enum wrap to throw in functions that returned non-jsvalues (which happens a lot).
Now, with this PR the throw methods have a generic `JsResult<R>` return that can return in any `JsResult<T>` returning function. Which cleans the API and makes the user experience a bit better.

```rust
return Err(context.construct_type_error("..."));
// to
return context.throw_type_error("...");
```

boa/src/bigint.rs

@@ -166,7 +166,7 @@ impl JsBigInt {
         let y = if let Some(y) = y.inner.to_biguint() {
             y
         } else {
-            return Err(context.construct_range_error("BigInt negative exponent"));
+            return context.throw_range_error("BigInt negative exponent");
         };
 
         let num_bits = (x.inner.bits() as f64
@@ -175,7 +175,7 @@ impl JsBigInt {
             + 1f64;
 
         if num_bits > 1_000_000_000f64 {
-            return Err(context.construct_range_error("Maximum BigInt size exceeded"));
+            return context.throw_range_error("Maximum BigInt size exceeded");
         }
 
         Ok(Self::new(x.inner.as_ref().clone().pow(y)))
@@ -192,7 +192,7 @@ impl JsBigInt {
 
             Ok(Self::new(inner))
         } else {
-            Err(context.construct_range_error("Maximum BigInt size exceeded"))
+            context.throw_range_error("Maximum BigInt size exceeded")
         }
     }
 
@@ -207,7 +207,7 @@ impl JsBigInt {
 
             Ok(Self::new(inner))
         } else {
-            Err(context.construct_range_error("Maximum BigInt size exceeded"))
+            context.throw_range_error("Maximum BigInt size exceeded")
         }
     }
 

boa/src/builtins/array/mod.rs

@@ -165,7 +165,7 @@ impl Array {
                 let int_len = len.to_u32(context).unwrap();
                 // ii. If SameValueZero(intLen, len) is false, throw a RangeError exception.
                 if !JsValue::same_value_zero(&int_len.into(), len) {
-                    return Err(context.construct_range_error("invalid array length"));
+                    return context.throw_range_error("invalid array length");
                 }
                 int_len
             };
@@ -210,7 +210,7 @@ impl Array {
     ) -> JsResult<JsObject> {
         // 1. If length > 2^32 - 1, throw a RangeError exception.
         if length > 2usize.pow(32) - 1 {
-            return Err(context.construct_range_error("array exceeded max size"));
+            return context.throw_range_error("array exceeded max size");
         }
         // 7. Return A.
         // 2. If proto is not present, set proto to %Array.prototype%.
@@ -365,7 +365,7 @@ impl Array {
                     .unwrap(),
             )
         } else {
-            Err(context.construct_type_error("Symbol.species must be a constructor"))
+            context.throw_type_error("Symbol.species must be a constructor")
         }
     }
 
@@ -1669,8 +1669,8 @@ impl Array {
                 } else {
                     // 1. If targetIndex >= 2^53 - 1, throw a TypeError exception
                     if target_index >= Number::MAX_SAFE_INTEGER as u64 {
-                        return Err(context
-                            .construct_type_error("Target index exceeded max safe integer value"));
+                        return context
+                            .throw_type_error("Target index exceeded max safe integer value");
                     }
 
                     // 2. Perform ? CreateDataPropertyOrThrow(target, targetIndex, element)

boa/src/builtins/array_buffer/mod.rs

@@ -363,7 +363,7 @@ impl ArrayBuffer {
         let src_block = if let Some(b) = &self.array_buffer_data {
             b
         } else {
-            return Err(context.construct_syntax_error("Cannot clone detached array buffer"));
+            return context.throw_syntax_error("Cannot clone detached array buffer");
         };
 
         {

boa/src/builtins/intl/mod.rs

@@ -93,9 +93,7 @@ impl Intl {
                 let k_value = o.get(k, context)?;
                 // ii. If Type(kValue) is not String or Object, throw a TypeError exception.
                 if !(k_value.is_object() || k_value.is_string()) {
-                    return Err(context
-                        .throw_type_error("locale should be a String or Object")
-                        .unwrap_err());
+                    return context.throw_type_error("locale should be a String or Object");
                 }
                 // iii. If Type(kValue) is Object and kValue has an [[InitializedLocale]] internal slot, then
                 // TODO: handle checks for InitializedLocale internal slot (there should be an if statement here)

boa/src/builtins/iterable/mod.rs

@@ -149,7 +149,7 @@ impl JsValue {
 
         // 4. If Type(iterator) is not Object, throw a TypeError exception.
         if !iterator.is_object() {
-            return Err(context.construct_type_error("the iterator is not an object"));
+            return context.throw_type_error("the iterator is not an object");
         }
 
         // 5. Let nextMethod be ? GetV(iterator, "next").

boa/src/builtins/json/mod.rs

@@ -448,7 +448,7 @@ impl Json {
 
         // 10. If Type(value) is BigInt, throw a TypeError exception.
         if value.is_bigint() {
-            return Err(context.construct_type_error("cannot serialize bigint to JSON"));
+            return context.throw_type_error("cannot serialize bigint to JSON");
         }
 
         // 11. If Type(value) is Object and IsCallable(value) is false, then
@@ -531,7 +531,7 @@ impl Json {
         // 1. If state.[[Stack]] contains value, throw a TypeError exception because the structure is cyclical.
         let limiter = RecursionLimiter::new(value);
         if limiter.live {
-            return Err(context.construct_type_error("cyclic object value"));
+            return context.throw_type_error("cyclic object value");
         }
 
         // 2. Append value to state.[[Stack]].
@@ -644,7 +644,7 @@ impl Json {
         // 1. If state.[[Stack]] contains value, throw a TypeError exception because the structure is cyclical.
         let limiter = RecursionLimiter::new(value);
         if limiter.live {
-            return Err(context.construct_type_error("cyclic object value"));
+            return context.throw_type_error("cyclic object value");
         }
 
         // 2. Append value to state.[[Stack]].

boa/src/builtins/number/mod.rs

@@ -222,8 +222,8 @@ impl Number {
         let this_str_num = if let Some(precision) = precision {
             // 5. If f < 0 or f > 100, throw a RangeError exception.
             if !(0..=100).contains(&precision) {
-                return Err(context
-                    .construct_range_error("toExponential() argument must be between 0 and 100"));
+                return context
+                    .throw_range_error("toExponential() argument must be between 0 and 100");
             }
             f64_to_exponential_with_precision(this_num, precision as usize)
         } else {
@@ -256,9 +256,8 @@ impl Number {
                 0..=100 => n.to_integer(context)? as usize,
                 // 4, 5. If f < 0 or f > 100, throw a RangeError exception.
                 _ => {
-                    return Err(context.construct_range_error(
-                        "toFixed() digits argument must be between 0 and 100",
-                    ))
+                    return context
+                        .throw_range_error("toFixed() digits argument must be between 0 and 100")
                 }
             },
             // 3. If fractionDigits is undefined, then f is 0.

boa/src/builtins/regexp/mod.rs

@@ -332,8 +332,8 @@ impl RegExp {
         // 14. Set obj.[[RegExpMatcher]] to the Abstract Closure that evaluates parseResult by applying the semantics provided in 22.2.2 using patternCharacters as the pattern's List of SourceCharacter values and F as the flag parameters.
         let matcher = match Regex::with_flags(&p, f.as_ref()) {
             Err(error) => {
-                return Err(context
-                    .construct_syntax_error(format!("failed to create matcher: {}", error.text)));
+                return context
+                    .throw_syntax_error(format!("failed to create matcher: {}", error.text));
             }
             Ok(val) => val,
         };
@@ -779,9 +779,7 @@ impl RegExp {
 
             // b. If Type(result) is neither Object nor Null, throw a TypeError exception.
             if !result.is_object() && !result.is_null() {
-                return Err(
-                    context.construct_type_error("regexp exec returned neither object nor null")
-                );
+                return context.throw_type_error("regexp exec returned neither object nor null");
             }
 
             // c. Return result.
@@ -790,7 +788,7 @@ impl RegExp {
 
         // 5. Perform ? RequireInternalSlot(R, [[RegExpMatcher]]).
         if !this.is_regexp() {
-            return Err(context.construct_type_error("RegExpExec called with invalid value"));
+            return context.throw_type_error("RegExpExec called with invalid value");
         }
 
         // 6. Return ? RegExpBuiltinExec(R, S).
@@ -814,9 +812,7 @@ impl RegExp {
             if let Some(rx) = obj.as_regexp() {
                 rx.clone()
             } else {
-                return Err(
-                    context.construct_type_error("RegExpBuiltinExec called with invalid value")
-                );
+                return context.throw_type_error("RegExpBuiltinExec called with invalid value");
             }
         };
 
@@ -870,9 +866,8 @@ impl RegExp {
             ) {
                 Ok(s) => s.len(),
                 Err(_) => {
-                    return Err(context.construct_type_error(
-                        "Failed to get byte index from utf16 encoded string",
-                    ))
+                    return context
+                        .throw_type_error("Failed to get byte index from utf16 encoded string")
                 }
             };
             let r = matcher.find_from(&input, last_byte_index).next();
@@ -1046,9 +1041,8 @@ impl RegExp {
         let rx = if let Some(rx) = this.as_object() {
             rx
         } else {
-            return Err(context.construct_type_error(
-                "RegExp.prototype.match method called on incompatible value",
-            ));
+            return context
+                .throw_type_error("RegExp.prototype.match method called on incompatible value");
         };
 
         // 3. Let S be ? ToString(string).
@@ -1495,9 +1489,9 @@ impl RegExp {
         let rx = if let Some(rx) = this.as_object() {
             rx
         } else {
-            return Err(context.construct_type_error(
+            return context.throw_type_error(
                 "RegExp.prototype[Symbol.search] method called on incompatible value",
-            ));
+            );
         };
 
         // 3. Let S be ? ToString(string).
@@ -1557,9 +1551,8 @@ impl RegExp {
         let rx = if let Some(rx) = this.as_object() {
             rx
         } else {
-            return Err(context.construct_type_error(
-                "RegExp.prototype.split method called on incompatible value",
-            ));
+            return context
+                .throw_type_error("RegExp.prototype.split method called on incompatible value");
         };
 
         // 3. Let S be ? ToString(string).