calculator-react

A simple calculator application using JavaScript library React JS

##Information

• Two react objects Square and Board are created. Square renders a square with a props 'number'. Board renders number of squares(In my case 16 squares)

• var lastCharacter = txtString.value.substr(txtString.value.length - 1); This assigns previous character to the variable lastCharacter.

• if (lastCharacter<'0' || lastCharacter>'9') This condition is to check whether last character is numeric or not.

• if (this.props.number<'0' || this.props.number>'9') This condition is to check whether currently entered character is numeric or not.

• If two symbols(non numeric characters) entered together, It prevents lastone from appending in the textbox. and, Initially anything other than numbers are restricted to enter.

• txtString.value+=this.props.number; This apppends currentle pressed value to the existing value of the textbox.

• result= eval(txtString.value); Here, eval is a builtin js function, it does maths operation on well formatted combination of numeric and symbols.so, we have tried to avoid all unexpected characters from above to make string acceptable for eval function.

• txtString.focus(); It is kept to return focus to the textbox immediately after pressed the button.

##Dependencies needed react.js and react-dom.js are included in js folder. browser.min.js is to run JSX, CDN is included.

##Demo http://projects.psuresh.com.np/calculator