Add util functions for null/undefined checks, organize tests into sections

src/common/all_test.ts

@@ -19,15 +19,7 @@ const {
 	testSuite,
 } = await getTestRunner();
 
-const encoder = new TextEncoder();
-const testKeyMap = (codes: string[], expected: string) => {
-	codes.forEach((code) => {
-		assertEquals(Fn.readKey(encoder.encode(code)), expected);
-	});
-};
-
-testSuite({
-	'ANSI utils': {
+const ANSITest = {
 	'moveCursor()': () => {
 		assertEquals(Ansi.moveCursor(1, 2), '\x1b[2;3H');
 	},
@@ -37,8 +29,11 @@ testSuite({
 	'moveCursorDown()': () => {
 		assertEquals(Ansi.moveCursorDown(7), '\x1b[7B');
 	},
-	},
-	Buffer: {
+};
+
+// ----------------------------------------------------------------------------
+
+const BufferTest = {
 	'new Buffer': () => {
 		const b = new Buffer();
 		assertInstanceOf(b, Buffer);
@@ -76,8 +71,11 @@ testSuite({
 
 		assertEquals(b.strlen(), 0);
 	},
-	},
-	Document: {
+};
+
+// ----------------------------------------------------------------------------
+
+const DocumentTest = {
 	'.default': () => {
 		const doc = Document.default();
 		assertEquals(doc.numRows, 0);
@@ -120,14 +118,20 @@ testSuite({
 		doc.delete(Position.at(3, 0));
 		assertEquals(doc.row(0)?.toString(), 'fooar');
 	},
-	},
-	Editor: {
+};
+
+// ----------------------------------------------------------------------------
+
+const EditorTest = {
 	'new Editor': () => {
 		const e = new Editor(defaultTerminalSize);
 		assertInstanceOf(e, Editor);
 	},
-	},
-	Position: {
+};
+
+// ----------------------------------------------------------------------------
+
+const PositionTest = {
 	'.default': () => {
 		const p = Position.default();
 		assertEquals(p.x, 0);
@@ -151,8 +155,11 @@ testSuite({
 		assertEquals(p2.x, 1);
 		assertEquals(p2.y, 2);
 	},
-	},
-	Row: {
+};
+
+// ----------------------------------------------------------------------------
+
+const RowTest = {
 	'.default': () => {
 		const row = Row.default();
 		assertEquals(row.toString(), '');
@@ -233,8 +240,28 @@ testSuite({
 		assertEquals(aCx, cx);
 		assertEquals(aRx, rx);
 	},
+};
+
+// ----------------------------------------------------------------------------
+
+const fnTest = {
+	'defined()': () => {
+		const { defined } = Fn;
+		assertFalse(defined(null));
+		assertFalse(defined(void 0));
+		assertFalse(defined(undefined));
+		assertTrue(defined(0));
+		assertTrue(defined(false));
+	},
+	'nullish()': () => {
+		const { nullish } = Fn;
+
+		assertTrue(nullish(null));
+		assertTrue(nullish(void 0));
+		assertTrue(nullish(undefined));
+		assertFalse(nullish(0));
+		assertFalse(nullish(false));
 	},
-	'fns': {
 	'arrayInsert() strings': () => {
 		const { arrayInsert } = Fn;
 
@@ -347,8 +374,19 @@ testSuite({
 		assertEquals(truncate('😺😸😹', 5), '😺😸😹');
 		assertEquals(truncate('👨‍👩‍👧‍👦', 5), '👨‍👩‍👧');
 	},
-	},
-	'readKey()': {
+};
+
+// ----------------------------------------------------------------------------
+
+const encoder = new TextEncoder();
+
+const testKeyMap = (codes: string[], expected: string) => {
+	codes.forEach((code) => {
+		assertEquals(Fn.readKey(encoder.encode(code)), expected);
+	});
+};
+
+const readKeyTest = {
 	'empty input': () => {
 		assertEquals(Fn.readKey(new Uint8Array(0)), '');
 	},
@@ -385,5 +423,19 @@ testSuite({
 	'End': () =>
 		testKeyMap(['\x1b[4~', '\x1b[8~', '\x1b[F', '\x1bOF'], KeyCommand.End),
 	'Enter': () => testKeyMap(['\n', '\r', '\v'], KeyCommand.Enter),
-	},
+};
+
+// ----------------------------------------------------------------------------
+// Test Suite Setup
+// ----------------------------------------------------------------------------
+
+testSuite({
+	'ANSI utils': ANSITest,
+	Buffer: BufferTest,
+	Document: DocumentTest,
+	Editor: EditorTest,
+	Position: PositionTest,
+	Row: RowTest,
+	fns: fnTest,
+	'readKey()': readKeyTest,
 });

src/common/document.ts

@@ -81,7 +81,7 @@ export class Document {
 			const row = this.#rows[potential.y];
 
 			// Okay, we have to take the Javascript string index (potential.x), convert
-			// it to the Row character index, and then convert that to the Row render index
+			// it to the Row 'character' index, and then convert that to the Row render index
 			// so that the highlighted color starts in the right place.
 			const start = row.cxToRx(row.byteIndexToCharIndex(potential.x));
 

src/common/fns.ts

@@ -11,6 +11,20 @@ const decoder = new TextDecoder();
  */
 export const noop = () => {};
 
+/**
+ * Does a value exist? (not null or undefined)
+ */
+export function defined(v: unknown): boolean {
+	return v !== null && typeof v !== 'undefined';
+}
+
+/**
+ * Is the value null or undefined?
+ */
+export function nullish(v: unknown): boolean {
+	return v === null || typeof v === 'undefined';
+}
+
 /**
  * Convert input from ANSI escape sequences into a form
  * that can be more easily mapped to editor commands

src/common/row.ts

@@ -107,6 +107,9 @@ export class Row {
 		return this.byteIndexToCharIndex(byteCount);
 	}
 
+	/**
+	 * Convert the raw row offset to the equivalent offset for screen rendering
+	 */
 	public cxToRx(cx: number): number {
 		let rx = 0;
 		let j;
@@ -120,6 +123,9 @@ export class Row {
 		return rx;
 	}
 
+	/**
+	 * Convert the screen rendering row offset to the file row offset
+	 */
 	public rxToCx(rx: number): number {
 		let curRx = 0;
 		let cx = 0;
@@ -137,6 +143,10 @@ export class Row {
 		return cx;
 	}
 
+	/**
+	 * Convert the index of a JS string into the equivalent
+	 * 'unicode character' index
+	 */
 	public byteIndexToCharIndex(byteIndex: number): number {
 		if (this.toString().length === this.chars.length) {
 			return byteIndex;
@@ -154,6 +164,10 @@ export class Row {
 		return this.chars.length;
 	}
 
+	/**
+	 * Convert the 'unicode character' index into the equivalent
+	 * JS string index
+	 */
 	public charIndexToByteIndex(charIndex: number): number {
 		if (charIndex === 0 || this.toString().length === this.chars.length) {
 			return charIndex;