Port the ResultSet class

lib/finder.d.ts

@@ -0,0 +1,49 @@
+/**
+ * Finds the instances of an executable in the system path.
+ */
+export declare class Finder {
+	#private;
+	/**
+	 * The list of executable file extensions.
+	 */
+	readonly extensions: Set<string>;
+	/**
+	 * The list of system paths.
+	 */
+	readonly paths: Set<string>;
+	/**
+	 * Creates a new finder.
+	 * @param options An object providing values to initialize this instance.
+	 */
+	constructor(options?: FinderOptions);
+	/**
+	 * Value indicating whether the current platform is Windows.
+	 */
+	static get isWindows(): boolean;
+	/**
+	 * Finds the instances of an executable in the system path.
+	 * @param command The command to be resolved.
+	 * @returns The paths of the executables found.
+	 */
+	find(command: string): AsyncGenerator<string, void>;
+	/**
+	 * Gets a value indicating whether the specified file is executable.
+	 * @param file The path of the file to be checked.
+	 * @returns `true` if the specified file is executable, otherwise `false`.
+	 */
+	isExecutable(file: string): Promise<boolean>;
+}
+/**
+ * Defines the options of a {@link Finder} instance.
+ */
+export type FinderOptions = Partial<{
+	/**
+	 * The list of executable file extensions.
+	 */
+	extensions: Array<string>;
+	/**
+	 * The list of system paths.
+	 */
+	paths: Array<string>;
+}>;
+//# sourceMappingURL=finder.d.ts.map

lib/result_set.d.ts

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+import {Finder} from "./finder.js";
+
+/**
+ * Provides convenient access to the stream of search results.
+ */
+export class ResultSet {
+
+	/**
+	 * Creates a new result set.
+	 * @param command The searched command.
+	 * @param finder The finder used to perform the search.
+	 */
+	constructor(command: string, finder: Finder);
+
+	/**
+	 * Returns all instances of the searched command.
+	 * @returns All search results.
+	 */
+	all(): Promise<Array<string>>;
+
+	/**
+	 * Returns the first instance of the searched command.
+	 * @returns The first search result.
+	 */
+	first(): Promise<string>;
+
+	/**
+	 * Returns a stream of instances of the searched command.
+	 * @returns A stream of the search results.
+	 */
+	stream(): AsyncGenerator<string, void>;
+}

src/finder.coffee

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+# Finds the instances of an executable in the system path.
+export class Finder

src/result_set.coffee

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+import {delimiter} from "node:path";
+import {Finder} from "./finder.js";
+
+# Provides convenient access to the stream of search results.
+export class ResultSet
+
+	# Creates a new result set.
+	constructor: (command, finder) ->
+
+		# The searched command.
+		@_command = command
+
+		# The finder used to perform the search.
+		@_finder = finder
+
+	# Returns all instances of the searched command.
+	all: ->
+		executables = new Set
+		executables.add path for await path from @stream()
+		if executables.size then Array.from executables else
+			paths = Array.from(@_finder.paths).join if Finder.isWindows then ";" else delimiter
+			throw Error "No \"#{@_command}\" in (#{paths})."
+
+	# Returns the first instance of the searched command.
+	first: ->
+		{value} = await @stream().next()
+		if value then value else
+			paths = Array.from(@_finder.paths).join if Finder.isWindows then ";" else delimiter
+			throw Error "No \"#{@_command}\" in (#{paths})."
+
+	# Returns a stream of instances of the searched command.
+	stream: -> @_finder.find @_command