Method chooseOperation

Calculator/app.js:24–33

(operation)

    }

    chooseOperation(operation){
        if(this.operation === '')
            return;
        if(this.previousOperant !== ''){
            this.compute();
        }    
        this.operation = operation;
        this.previousOperant = this.currentOperant;
        this.currentOperant = '';
    }

    compute(){
        let computation;