Add one-variable-per-declaration tslint rule

Multiple declarations per line makes it more difficult to read what
exactly is declared and generally makes code more verbose and less
likely to fill in types

src/InputHandler.ts

@@ -189,14 +189,12 @@ export class InputHandler implements IInputHandler {
    * Insert Ps (Blank) Character(s) (default = 1) (ICH).
    */
   public insertChars(params: number[]): void {
-    let param, row, j, ch;
-
-    param = params[0];
+    let param = params[0];
     if (param < 1) param = 1;
 
-    row = this._terminal.buffer.y + this._terminal.buffer.ybase;
-    j = this._terminal.buffer.x;
-    ch = [this._terminal.eraseAttr(), ' ', 1]; // xterm
+    const row = this._terminal.buffer.y + this._terminal.buffer.ybase;
+    let j = this._terminal.buffer.x;
+    const ch = [this._terminal.eraseAttr(), ' ', 1]; // xterm
 
     while (param-- && j < this._terminal.cols) {
       this._terminal.buffer.lines.get(row).splice(j++, 0, ch);
@@ -325,9 +323,8 @@ export class InputHandler implements IInputHandler {
    * Cursor Position [row;column] (default = [1,1]) (CUP).
    */
   public cursorPosition(params: number[]): void {
-    let row, col;
-
-    row = params[0] - 1;
+    let col: number;
+    let row: number = params[0] - 1;
 
     if (params.length >= 2) {
       col = params[1] - 1;
@@ -439,14 +436,13 @@ export class InputHandler implements IInputHandler {
    * Insert Ps Line(s) (default = 1) (IL).
    */
   public insertLines(params: number[]): void {
-    let param, row, j;
-
-    param = params[0];
+    let param: number = params[0];
     if (param < 1) {
       param = 1;
     }
-    row = this._terminal.buffer.y + this._terminal.buffer.ybase;
+    let row: number = this._terminal.buffer.y + this._terminal.buffer.ybase;
 
+    let j: number;
     j = this._terminal.rows - 1 - this._terminal.buffer.scrollBottom;
     j = this._terminal.rows - 1 + this._terminal.buffer.ybase - j + 1;
 
@@ -475,14 +471,13 @@ export class InputHandler implements IInputHandler {
    * Delete Ps Line(s) (default = 1) (DL).
    */
   public deleteLines(params: number[]): void {
-    let param, row, j;
-
-    param = params[0];
+    let param = params[0];
     if (param < 1) {
       param = 1;
     }
-    row = this._terminal.buffer.y + this._terminal.buffer.ybase;
+    const row: number = this._terminal.buffer.y + this._terminal.buffer.ybase;
 
+    let j: number;
     j = this._terminal.rows - 1 - this._terminal.buffer.scrollBottom;
     j = this._terminal.rows - 1 + this._terminal.buffer.ybase - j;
 
@@ -509,15 +504,13 @@ export class InputHandler implements IInputHandler {
    * Delete Ps Character(s) (default = 1) (DCH).
    */
   public deleteChars(params: number[]): void {
-    let param, row, ch;
-
-    param = params[0];
+    let param: number = params[0];
     if (param < 1) {
       param = 1;
     }
 
-    row = this._terminal.buffer.y + this._terminal.buffer.ybase;
-    ch = [this._terminal.eraseAttr(), ' ', 1]; // xterm
+    const row = this._terminal.buffer.y + this._terminal.buffer.ybase;
+    const ch = [this._terminal.eraseAttr(), ' ', 1]; // xterm
 
     while (param--) {
       this._terminal.buffer.lines.get(row).splice(this._terminal.buffer.x, 1);
@@ -558,16 +551,14 @@ export class InputHandler implements IInputHandler {
    * Erase Ps Character(s) (default = 1) (ECH).
    */
   public eraseChars(params: number[]): void {
-    let param, row, j, ch;
-
-    param = params[0];
+    let param = params[0];
     if (param < 1) {
       param = 1;
     }
 
-    row = this._terminal.buffer.y + this._terminal.buffer.ybase;
-    j = this._terminal.buffer.x;
-    ch = [this._terminal.eraseAttr(), ' ', 1]; // xterm
+    const row = this._terminal.buffer.y + this._terminal.buffer.ybase;
+    let j = this._terminal.buffer.x;
+    const ch = [this._terminal.eraseAttr(), ' ', 1]; // xterm
 
     while (param-- && j < this._terminal.cols) {
       this._terminal.buffer.lines.get(row)[j++] = ch;
@@ -619,9 +610,9 @@ export class InputHandler implements IInputHandler {
    * CSI Ps b  Repeat the preceding graphic character Ps times (REP).
    */
   public repeatPrecedingCharacter(params: number[]): void {
-    let param = params[0] || 1
-      , line = this._terminal.buffer.lines.get(this._terminal.buffer.ybase + this._terminal.buffer.y)
-      , ch = line[this._terminal.buffer.x - 1] || [this._terminal.defAttr, ' ', 1];
+    let param = params[0] || 1;
+    const line = this._terminal.buffer.lines.get(this._terminal.buffer.ybase + this._terminal.buffer.y);
+    const ch = line[this._terminal.buffer.x - 1] || [this._terminal.defAttr, ' ', 1];
 
     while (param--) {
       line[this._terminal.buffer.x++] = ch;
@@ -1203,14 +1194,13 @@ export class InputHandler implements IInputHandler {
       return;
     }
 
-    let l = params.length
-    , i = 0
-    , flags = this._terminal.curAttr >> 18
-    , fg = (this._terminal.curAttr >> 9) & 0x1ff
-    , bg = this._terminal.curAttr & 0x1ff
-    , p;
+    const l = params.length;
+    let flags = this._terminal.curAttr >> 18;
+    let fg = (this._terminal.curAttr >> 9) & 0x1ff;
+    let bg = this._terminal.curAttr & 0x1ff;
+    let p;
 
-    for (; i < l; i++) {
+    for (let i = 0; i < l; i++) {
       p = params[i];
       if (p >= 30 && p <= 37) {
         // fg color 8

src/Parser.ts

@@ -182,7 +182,12 @@ export class Parser {
    * @param data The data to parse.
    */
   public parse(data: string): ParserState {
-    let l = data.length, j, cs, ch, code, low;
+    const l = data.length;
+    let j;
+    let cs;
+    let ch;
+    let code;
+    let low;
 
     if (this._terminal.debug) {
       this._terminal.log('data: ' + data);

src/Terminal.ts

@@ -95,9 +95,9 @@ const tangoColors = [
 // Colors 0-15 + 16-255
 // Much thanks to TooTallNate for writing this.
 const defaultColors = (function() {
-  let colors = tangoColors.slice()
-  , r = [0x00, 0x5f, 0x87, 0xaf, 0xd7, 0xff]
-  , i;
+  let colors = tangoColors.slice();
+  let r = [0x00, 0x5f, 0x87, 0xaf, 0xd7, 0xff];
+  let i;
 
   // 16-231
   i = 0;
@@ -971,11 +971,11 @@ export class Terminal extends EventEmitter implements ITerminal {
     }
 
     function getButton(ev) {
-      let button
-      , shift
-      , meta
-      , ctrl
-      , mod;
+      let button;
+      let shift;
+      let meta;
+      let ctrl;
+      let mod;
 
       // two low bits:
       // 0 = left
@@ -1918,12 +1918,12 @@ export class Terminal extends EventEmitter implements ITerminal {
       this.setOption('scrollback', y);
     }
 
-    let line
-    , el
-    , i
-    , j
-    , ch
-    , addToY;
+    let line;
+    let el;
+    let i;
+    let j;
+    let ch;
+    let addToY;
 
     if (x === this.cols && y === this.rows) {
       // Check if we still need to measure the char size (fixes #785).
@@ -2426,8 +2426,8 @@ function wasMondifierKeyOnlyEvent(ev) {
 
 function keys(obj) {
   if (Object.keys) return Object.keys(obj);
-  let key, keys = [];
-  for (key in obj) {
+  const keys = [];
+  for (let key in obj) {
     if (Object.prototype.hasOwnProperty.call(obj, key)) {
       keys.push(key);
     }

src/handlers/Clipboard.test.ts

@@ -4,9 +4,9 @@ import * as Clipboard from './Clipboard';
 
 describe('evaluatePastedTextProcessing', function () {
   it('should replace carriage return + line feed with line feed on windows', function () {
-    const pastedText = 'foo\r\nbar\r\n',
-          processedText = Clipboard.prepareTextForTerminal(pastedText, false),
-          windowsProcessedText = Clipboard.prepareTextForTerminal(pastedText, true);
+    const pastedText = 'foo\r\nbar\r\n';
+    const processedText = Clipboard.prepareTextForTerminal(pastedText, false);
+    const windowsProcessedText = Clipboard.prepareTextForTerminal(pastedText, true);
 
     assert.equal(processedText, 'foo\r\nbar\r\n');
     assert.equal(windowsProcessedText, 'foo\rbar\r');

tslint.json

@@ -13,6 +13,10 @@
     "no-eval": true,
     "no-internal-module": true,
     "no-trailing-whitespace": true,
+    "one-variable-per-declaration": [
+      true,
+      true
+    ],
     "no-unsafe-finally": true,
     "no-var-keyword": true,
     "quotemark": [