refactor: replace deprecated String.prototype.substr() (#646)

`.substr()` is deprecated so we replace it with `.slice()` which works similarily but isn't deprecated. See also: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substr Signed-off-by: Lam Wei Li <[email protected]>

Author: lamweili

lib/parser-v3/index.ts

@@ -137,7 +137,7 @@ export function decodePacket (data, binaryType, utf8decode){
 type=data.charAt(0);
 
 if(type==='b'){
-returndecodeBase64Packet(data.substr(1),binaryType);
+returndecodeBase64Packet(data.slice(1),binaryType);
 }
 
 if(utf8decode){
@@ -152,7 +152,7 @@ export function decodePacket (data, binaryType, utf8decode){
 }
 
 if(data.length>1){
-return{type: packetslist[type],data: data.substring(1)};
+return{type: packetslist[type],data: data.slice(1)};
 }else{
 return{type: packetslist[type]};
 }
@@ -191,7 +191,7 @@ function tryDecode(data){
 
 exportfunctiondecodeBase64Packet(msg,binaryType){
 vartype=packetslist[msg.charAt(0)];
-vardata=Buffer.from(msg.substr(1),'base64');
+vardata=Buffer.from(msg.slice(1),'base64');
 if(binaryType==='arraybuffer'){
 varabv=newUint8Array(data.length);
 for(vari=0;i<abv.length;i++){
@@ -305,7 +305,7 @@ export function decodePayload (data, binaryType, callback){
 returncallback(err,0,1);
 }
 
-msg=data.substr(i+1,n);
+msg=data.slice(i+1,i+1+n);
 
 if(length!=msg.length){
 // parser error - ignoring payload

lib/server.ts

@@ -555,7 +555,7 @@ export class Server extends BaseServer{
 return;
 }
 
-consthead=Buffer.from(upgradeHead);// eslint-disable-line node/no-deprecated-api
+consthead=Buffer.from(upgradeHead);
 upgradeHead=null;
 
 // delegate to ws
@@ -643,7 +643,7 @@ export class Server extends BaseServer{
 path+="/";
 
 functioncheck(req){
-returnpath===req.url.substr(0,path.length);
+returnpath===req.url.slice(0,path.length);
 }
 
 // cache and clean up listeners

test/server.js

@@ -181,7 +181,7 @@ describe("server", () =>{
 .get(`http://localhost:${port}/engine.io/`)
 .query({transport: "polling",EIO: 4})
 .end((err,res)=>{
-constsid=JSON.parse(res.text.substring(1)).sid;
+constsid=JSON.parse(res.text.slice(1)).sid;
 
 request
 .get(`http://localhost:${port}/engine.io/`)
@@ -3357,7 +3357,7 @@ describe("server", () =>{
 expect(res.headers["set-cookie"].length).to.be(2);
 expect(res.headers["set-cookie"][1]).to.be("mycookie=456");
 
-constsid=JSON.parse(res.text.substring(5)).sid;
+constsid=JSON.parse(res.text.slice(5)).sid;
 
 request
 .post(`http://localhost:${port}/engine.io/`)
@@ -3394,7 +3394,7 @@ describe("server", () =>{
 expect(res.headers["set-cookie"].length).to.be(2);
 expect(res.headers["set-cookie"][1]).to.be("mycookie=456");
 
-constsid=JSON.parse(res.text.substring(5)).sid;
+constsid=JSON.parse(res.text.slice(5)).sid;
 
 request
 .post(`http://localhost:${port}/engine.io/`)