Enforce const enums

Fixes #1408

src/AccessibilityManager.ts

@@ -12,7 +12,7 @@ import { IDisposable } from 'xterm';
 
 const MAX_ROWS_TO_READ = 20;
 
-enum BoundaryPosition {
+const enum BoundaryPosition {
   TOP,
   BOTTOM
 }

src/Parser.ts

@@ -150,7 +150,7 @@ csiStateHandler['s'] = (handler, params) => handler.saveCursor(params);
 csiStateHandler['u'] = (handler, params) => handler.restoreCursor(params);
 csiStateHandler[C0.CAN] = (handler, params, prefix, postfix, parser) => parser.setState(ParserState.NORMAL);
 
-export enum ParserState {
+export const enum ParserState {
   NORMAL = 0,
   ESCAPED = 1,
   CSI_PARAM = 2,

src/SelectionManager.ts

@@ -54,7 +54,7 @@ interface IWordPosition {
 /**
  * A selection mode, this drives how the selection behaves on mouse move.
  */
-enum SelectionMode {
+const enum SelectionMode {
   NORMAL,
   WORD,
   LINE

src/Types.ts

@@ -17,7 +17,7 @@ export type LineData = CharData[];
 export type LinkMatcherHandler = (event: MouseEvent, uri: string) => void;
 export type LinkMatcherValidationCallback = (uri: string, callback: (isValid: boolean) => void) => void;
 
-export enum LinkHoverEventTypes {
+export const enum LinkHoverEventTypes {
   HOVER = 'linkhover',
   TOOLTIP = 'linktooltip',
   LEAVE = 'linkleave'

src/handlers/AltClickHandler.ts

@@ -6,7 +6,7 @@
 import { ITerminal, ICircularList, LineData } from '../Types';
 import { C0 } from '../EscapeSequences';
 
-enum Direction {
+const enum Direction {
   UP = 'A',
   DOWN = 'B',
   RIGHT = 'C',

src/renderer/Types.ts

@@ -10,7 +10,7 @@ import { IColorSet } from '../shared/Types';
 /**
  * Flags used to render terminal text properly.
  */
-export enum FLAGS {
+export const enum FLAGS {
   BOLD = 1,
   UNDERLINE = 2,
   BLINK = 4,

tslint.json

@@ -92,6 +92,9 @@
     "naming-convention": [
       true,
       {"type": "property", "modifiers": ["public", "static", "const"], "format": "UPPER_CASE"}
+    ],
+    "prefer-const-enum": [
+      true
     ]
   }
 }