New linter fixes

js/applesoft/compiler.ts

@@ -61,7 +61,7 @@ class LineBuffer implements IterableIterator<string> {
         return new LineBuffer(this.line, this.curChar);
     }
 
-    next(): IteratorResult<string> {
+    next(): IteratorResult<string, string | undefined> {
         if (this.atEnd()) {
             return { done: true, value: undefined };
         }
@@ -123,8 +123,6 @@ class LineBuffer implements IterableIterator<string> {
 export default class ApplesoftCompiler {
     private lines: Map<number, byte[]> = new Map();
 
-    constructor() { }
-
     /**
      * Loads an AppleSoft BASIC program into memory.
      *
@@ -197,7 +195,7 @@ export default class ApplesoftCompiler {
                         // Backup to before the token
                         lineBuffer.backup();
                         // and emit the 'A' (upper- or lower-case)
-                        return lineBuffer.next().value.charCodeAt(0);
+                        return lineBuffer.next().value?.charCodeAt(0) ?? 0;
                     }
                 }
                 return STRING_TO_TOKEN[possibleToken];
@@ -205,7 +203,7 @@ export default class ApplesoftCompiler {
         }
 
         // If not a token, output the character upper-cased
-        return lineBuffer.next().value.toUpperCase().charCodeAt(0);
+        return lineBuffer.next().value?.toUpperCase().charCodeAt(0) ?? 0;
     }
 
     private compileLine(line: string | null | undefined) {
@@ -306,7 +304,7 @@ export default class ApplesoftCompiler {
         const lineNumbers = [...this.lines.keys()].sort();
 
         for (const lineNo of lineNumbers) {
-            const lineBytes = this.lines.get(lineNo)!;
+            const lineBytes = this.lines.get(lineNo) || [];
             const nextLineAddr = programStart + result.length + 4
                 + lineBytes.length + 1; // +1 for the zero at end of line
             result.push(nextLineAddr & 0xff, nextLineAddr >> 8);

js/applesoft/decompiler.ts

@@ -79,12 +79,12 @@ export default class ApplesoftDecompiler {
         let offset = 0;
         let nextLineAddr = this.wordAt(offset);
         let nextLineNo = this.wordAt(offset + 2);
-        while (nextLineAddr != 0 && nextLineNo < from) {
+        while (nextLineAddr !== 0 && nextLineNo < from) {
             offset = nextLineAddr;
             nextLineAddr = this.wordAt(offset);
             nextLineNo = this.wordAt(offset + 2);
         }
-        while (nextLineAddr != 0 && nextLineNo <= to) {
+        while (nextLineAddr !== 0 && nextLineNo <= to) {
             callback(offset + 2);
             offset = nextLineAddr - this.base;
             nextLineAddr = this.wordAt(offset);
@@ -105,14 +105,14 @@ export default class ApplesoftDecompiler {
         if (options.apple2 === 'e') {
             line += ' '; // D6F9: JSR SPCLIN
         }
-        line += lineNo + ' '; // D6FC, always 1 space after line number
+        line += `${lineNo} `; // D6FC, always 1 space after line number
         offset += 2;
 
         // In the original ROM, the line length is checked immediately
         // after the line number is printed. For simplicity, this method
         // always assumes that there is space for one token—which would
         // have been the case on a realy Apple.
-        while (this.program[offset] != 0) {
+        while (this.program[offset] !== 0) {
             const token = this.program[offset];
             if (token >= 0x80 && token <= 0xea) {
                 line += ' '; // D750, always put a space in front of token
@@ -193,7 +193,7 @@ export default class ApplesoftDecompiler {
         spaceIf = (nextToken: string) => /^\d/.test(nextToken);
         offset += 2;
 
-        while (this.program[offset] != 0) {
+        while (this.program[offset] !== 0) {
             const token = this.program[offset];
             let tokenString: string;
             if (token >= 0x80 && token <= 0xea) {
@@ -235,10 +235,10 @@ export default class ApplesoftDecompiler {
         let spaceIf: (char: byte) => boolean = () => false;
 
         const lineNo = this.wordAt(offset);
-        result += lineNo + ' ';
+        result += `${lineNo} `;
         offset += 2;
 
-        while (this.program[offset] != 0) {
+        while (this.program[offset] !== 0) {
             const token = this.program[offset];
             let tokenString: string;
             if (token >= 0x80 && token <= 0xea) {