/**

* @license Apache-2.0

*

* Copyright (c) 2022 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';

// VARIABLES //

// Using `Function#toString` bypasses a value's own `toString` method to provide an extra, but not security proof, precaution to prevent a provided function from impersonating a native function:

var fcn2str = Function.prototype.toString;

// MAIN //

/**

* Returns a string representing the source code of a provided function.

*

* ## Notes

*

* - If called on built-in functions, functions created by `Function.prototype.bind()`, or other non-JavaScript functions, the function returns a "native" function string similar to the following:

*

* ```text

* "function foo() { [native code] }"

* ```

*

* For intrinsic object methods and functions, `foo` is the initial name of the function.

*

* - If called on a function created by the `Function` constructor, the function returns the source code of a synthesized function declaration having the name "anonymous" and using the provided parameters and function body.

*

* - Starting in ES2018, the ECMAScript specification requires that the returned string contain the exact same source code as it was declared, including any whitespace and/or comments. If the host is unable to access the source code, the specification requires that the returned string be the native function string.

*

* @param {Function} fcn - input function

* @throws {TypeError} must provide a function

* @returns {string} string representing function source code

*

* @example

* function add( x, y ) {

* return x + y;

* }

*

* var str = function2string( add );

* // e.g., returns 'function add( x, y ) {\n return x + y;\n}'

*/

function function2string( fcn ) {

return fcn2str.call( fcn );

}

// EXPORTS //

module.exports = function2string;