feat: replace var with const and let (#80)

.travis.yml

@@ -4,6 +4,7 @@ node_js:
   - "9"
   - "10"
   - "11"
+  - "12"
 notifications:
   email:
     on_success: never

lib/layer.js

@@ -1,6 +1,6 @@
-var debug = require('debug')('koa-router');
-var { pathToRegexp, compile, parse } = require('path-to-regexp');
-var uri = require('urijs');
+const debug = require('debug')('koa-router');
+const { pathToRegexp, compile, parse } = require('path-to-regexp');
+const uri = require('urijs');
 
 module.exports = Layer;
 
@@ -25,17 +25,17 @@ function Layer(path, methods, middleware, opts) {
   this.paramNames = [];
   this.stack = Array.isArray(middleware) ? middleware : [middleware];
 
-  for(var i = 0; i < methods.length; i++) {
-    var l = this.methods.push(methods[i].toUpperCase());
+  for(let i = 0; i < methods.length; i++) {
+    const l = this.methods.push(methods[i].toUpperCase());
     if (this.methods[l-1] === 'GET') {
        this.methods.unshift('HEAD');
     }
   }
 
   // ensure middleware is a function
-  for (var i = 0; i < this.stack.length; i++) {
-    var fn = this.stack[i];
-    var type = (typeof fn);
+  for (let i = 0; i < this.stack.length; i++) {
+    const fn = this.stack[i];
+    const type = (typeof fn);
     if (type !== 'function') {
       throw new Error(
         methods.toString() + " `" + (this.opts.name || path) +"`: `middleware` "
@@ -73,11 +73,11 @@ Layer.prototype.match = function (path) {
  */
 
 Layer.prototype.params = function (path, captures, existingParams) {
-  var params = existingParams || {};
+  const params = existingParams || {};
 
-  for (var len = captures.length, i=0; i<len; i++) {
+  for (let len = captures.length, i=0; i<len; i++) {
     if (this.paramNames[i]) {
-      var c = captures[i];
+      const c = captures[i];
       params[this.paramNames[i].name] = c ? safeDecodeURIComponent(c) : c;
     }
   }
@@ -115,8 +115,8 @@ Layer.prototype.captures = function (path) {
  */
 
 Layer.prototype.url = function (params, options) {
-  var args = params;
-  var url = this.path.replace(/\(\.\*\)/g, '');
+  let args = params;
+  const url = this.path.replace(/\(\.\*\)/g, '');
 
   if (typeof params != 'object') {
     args = Array.prototype.slice.call(arguments);
@@ -126,14 +126,14 @@ Layer.prototype.url = function (params, options) {
     }
   }
 
-  var toPath = compile(url, options);
-  var replaced;
+  const toPath = compile(url, options);
+  let replaced;
 
-  var tokens = parse(url);
-  var replace = {};
+  const tokens = parse(url);
+  let replace = {};
 
   if (args instanceof Array) {
-    for (var len = tokens.length, i=0, j=0; i<len; i++) {
+    for (let len = tokens.length, i=0, j=0; i<len; i++) {
       if (tokens[i].name) replace[tokens[i].name] = args[j++];
     }
   } else if (tokens.some(token => token.name)) {
@@ -145,7 +145,7 @@ Layer.prototype.url = function (params, options) {
   replaced = toPath(replace);
 
   if (options && options.query) {
-    var replaced = new uri(replaced)
+    replaced = new uri(replaced)
     replaced.search(options.query);
     return replaced.toString();
   }
@@ -177,18 +177,18 @@ Layer.prototype.url = function (params, options) {
  */
 
 Layer.prototype.param = function (param, fn) {
-  var stack = this.stack;
-  var params = this.paramNames;
-  var middleware = function (ctx, next) {
+  const stack = this.stack;
+  const params = this.paramNames;
+  const middleware = function (ctx, next) {
     return fn.call(this, ctx.params[param], ctx, next);
   };
   middleware.param = param;
 
-  var names = params.map(function (p) {
+  const names = params.map(function (p) {
     return p.name;
   });
 
-  var x = names.indexOf(param);
+  const x = names.indexOf(param);
   if (x > -1) {
     // iterate through the stack, to figure out where to place the handler fn
     stack.some(function (fn, i) {