refactor!: require nested struct types be struct constructors

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---

Author: kgryte

lib/node_modules/@stdlib/dstructs/struct/examples/nested_struct.js

@@ -52,7 +52,7 @@ var fields2 = [
 	{
 		'name': 'words',
 		'description': 'high and low words',
-		'type': new Struct1(),
+		'type': Struct1,
 		'enumerable': true,
 		'writable': true,
 		'castingMode': 'none'

lib/node_modules/@stdlib/dstructs/struct/examples/union_with_struct.js

@@ -57,7 +57,7 @@ var fields2 = [
 			{
 				'name': 'words',
 				'description': 'high and low words',
-				'type': new Struct1(),
+				'type': Struct1,
 				'enumerable': true,
 				'writable': true,
 				'castingMode': 'none'

lib/node_modules/@stdlib/dstructs/struct/lib/byte_length.js

@@ -35,7 +35,7 @@ var bytesPerElement = require( '@stdlib/ndarray/base/bytes-per-element' );
 function byteLength( obj ) {
 	var nb;
 	if ( obj.isStructType ) {
-		nb = obj.type.constructor.byteLength;
+		nb = obj.type.byteLength;
 	} else {
 		nb = bytesPerElement( obj.type );
 	}

lib/node_modules/@stdlib/dstructs/struct/lib/format_layout.js

@@ -106,10 +106,7 @@ function layoutFormat( fields ) {
 		}
 		// If the current type is a struct, we need to serialize and then post-process...
 		if ( o.isStructType ) {
-			tmp = o.type.toString({
-				'format': 'layout'
-			});
-			out.push( replace( tmp, re, replacer( o.byteOffset ) ) );
+			out.push( replace( o.type.layout, re, replacer( o.byteOffset ) ) );
 			continue;
 		}
 		// Format the field data:

lib/node_modules/@stdlib/dstructs/struct/lib/format_linear.js

@@ -65,6 +65,7 @@ function linearFormat( Struct, fields ) {
 	var N;
 	var o;
 	var f;
+	var t;
 	var i;
 	var j;
 	var k;
@@ -137,7 +138,12 @@ function linearFormat( Struct, fields ) {
 				k = i + 1;
 				while ( k < N && o.byteOffset === fields[ k ].byteOffset ) {
 					f = fields[ k ];
-					tmp.push( format( '%s<%s>[%u]', f.name, f.type, j%f.alignment ) );
+					if ( f.isStructType ) {
+						t = '<Struct>';
+					} else {
+						t = f.type;
+					}
+					tmp.push( format( '%s<%s>[%u]', f.name, t, j%f.alignment ) );
 					k += 1;
 				}
 				ufmt = format( ufmt, tmp.join( ', ' ) );

lib/node_modules/@stdlib/dstructs/struct/lib/get_struct.js

@@ -45,7 +45,7 @@ function getStruct( obj ) {
 	*/
 	function getter() {
 		var view = this[ PRIVATE_BUFFER ];
-		return new obj.type.constructor( view.buffer, view.byteOffset+obj.byteOffset, obj.byteLength ); // eslint-disable-line max-len
+		return new obj.type( view.buffer, view.byteOffset+obj.byteOffset, obj.byteLength ); // eslint-disable-line max-len
 	}
 }
 

lib/node_modules/@stdlib/dstructs/struct/lib/get_struct_array.js

@@ -53,7 +53,7 @@ function getStructArray( obj ) {
 		offset = view.byteOffset + obj.byteOffset;
 		out = [];
 		for ( i = 0; i < obj.length; i++ ) {
-			out.push( new obj.type.constructor( view.buffer, offset, obj.byteLength ) ); // eslint-disable-line max-len
+			out.push( new obj.type( view.buffer, offset, obj.byteLength ) );
 			offset += obj.byteOffset;
 		}
 		return out;

lib/node_modules/@stdlib/dstructs/struct/lib/is_struct.js renamed to lib/node_modules/@stdlib/dstructs/struct/lib/is_struct_instance.js

@@ -34,7 +34,7 @@ var PRIVATE_BUFFER = require( './private_buffer.js' );
 * @param {*} value - value to test
 * @returns {boolean} boolean indicating if a value is a `struct` instance
 */
-function isStruct( value ) {
+function isStructInstance( value ) {
 	// NOTE: the following is a relatively weak test, but we cannot use `instanceof` checks, etc, due to the factory nature of the implementation. Regardless, here, we are just trying to sniff out a `struct` type. If calling as a constructor later fails, we punt the responsibility off to the user to handle what should be an edge case. If, in the future, this check proves insufficient, we can add further "brand" checks...
 	return (
 		isObject( value ) &&
@@ -45,4 +45,4 @@ function isStruct( value ) {
 
 // EXPORTS //
 
-module.exports = isStruct;
+module.exports = isStructInstance;

lib/node_modules/@stdlib/dstructs/struct/lib/is_struct_type.js

@@ -0,0 +1,51 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var isPositiveInteger = require( '@stdlib/assert/is-positive-integer' ).isPrimitive;
+var isFunction = require( '@stdlib/assert/is-function' );
+
+
+// MAIN //
+
+/**
+* Returns a boolean indicating if a value is a `struct` instance.
+*
+* @private
+* @param {*} value - value to test
+* @returns {boolean} boolean indicating if a value is a `struct` instance
+*/
+function isStructType( value ) {
+	return (
+		isFunction( value ) &&
+		isPositiveInteger( value.alignment ) &&
+		isPositiveInteger( value.byteLength ) &&
+		isFunction( value.byteLengthOf ) &&
+		isFunction( value.byteOffsetOf ) &&
+		isFunction( value.bufferOf ) &&
+		isFunction( value.viewOf )
+	);
+}
+
+
+// EXPORTS //
+
+module.exports = isStructType;

lib/node_modules/@stdlib/dstructs/struct/lib/is_valid_type.js

@@ -23,7 +23,7 @@
 var contains = require( '@stdlib/array/base/assert/contains' );
 var join = require( '@stdlib/array/base/join' );
 var format = require( '@stdlib/string/format' );
-var isStruct = require( './is_struct.js' );
+var isStructType = require( './is_struct_type.js' );
 var DTYPES = require( './dtypes.js' );
 
 
@@ -37,10 +37,10 @@ var DTYPES = require( './dtypes.js' );
 * @returns {(null|TypeError)} error object or null
 */
 function isValidType( value ) {
-	if ( contains( DTYPES, value ) || isStruct( value ) ) {
+	if ( contains( DTYPES, value ) || isStructType( value ) ) {
 		return null;
 	}
-	return new TypeError( format( 'invalid argument. `%s` field must be either a `struct` or one of the following: "%s". Value: `%s`.', 'type', join( DTYPES, ', ' ), value ) );
+	return new TypeError( format( 'invalid argument. `%s` field must be either a struct type or one of the following: "%s". Value: `%s`.', 'type', join( DTYPES, ', ' ), value ) );
 }