Calculator App - Doesn't set at the end the string to "" empty value

Tell us what’s happening:
I have written the calculator app, it works for all 15 out of 16 test cases, however the last problem I can’t solve is regarding the this.setState({}) method. I have the state in the form of
After I press ‘=’ sign I set the this.state.calculationFinished:true
And on the next input it first checks calculationFinished and if it is true in the line 49 (link to codepen provided below), it calls the below:
operations:"", // this is the point where it doesn’t set operations to empty string
calculationFinished:false // at the same time calculationFinished however is successfully set to false

Your code so far
Link to CodePen:

Calculator CodePen

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Challenge: Build a JavaScript Calculator

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