cant send a message to a specific channel - node.js

Question

I have a simple dc bot, code goes like this. I tried to simplfy it to make it more readable
const client = new Discord.Client();
...
client.on('ready', () => {
client.channels.cache.get('315445287374028800').send("works here");
});
setInterval(( () =>{
try{
removeHTML(downloadHTML);
} catch(err){
console.log(err);
}
}),30000);
...
...
let removeHTML = function(callback){
client.channels.cache.get('315445287374028800').send("WORKS HERE");
readHTML();
...
}
let readHTML = function(){
console.log("dolar is read");
//client.channels.cache.get('315445287374028800').send("DOESNT WORK HERE");
fs.readFile(dir + '/index.html' , 'utf-8', function(err,html){
if(err)
console.log(err);
else{
//client.channels.cache.get('315445287374028800').send("DOESNT WORK HERE");
if(isPeak){
//client.channels.cache.get('315445287374028800').send("DOESNT WORK HERE");
}
}
});
}
seems like send function doesnt work in callback functions but how can i fix this?
Error type: same error for all ("DOESNT WORK HERE") lines :
TypeError: Cannot read property 'send' of undefined
at readHTML (C:\Users\user\Desktop\Discord Bot\index.js:142:18)
at Object.<anonymous> (C:\Users\user\Desktop\Discord Bot\index.js:182:1)
at Module._compile (internal/modules/cjs/loader.js:1015:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1035:10)
at Module.load (internal/modules/cjs/loader.js:879:32)
at Function.Module._load (internal/modules/cjs/loader.js:724:14)
at Function.executeUserEntryPoint [as runMain]

Answer 1

I have turned all functions to async-await instead and it worked