Array is being changed to String inside a arrow function

I am defining my variable as array and pushing values inside it. When I try to access this variable inside another method and apply push function on it, It says, Push is not defined. When I check the typeof of this variable it shows as String.

Any suggestions?

recipients = [];

....

 handleEmailChange(event) {

        const {name , value , dataset: {recipientIndex} } = event.target;
        this.toAddresses[recipientIndex][name] = value; 

    }

handleChange(event) {
        this.recipients = event.detail.value;
    }

 handleSend(event){

        this.toAddresses.forEach ( (address) => {

            const email = address.emailAddress;
            this.recipients.push(email); // ERRORS OUT