A String Containing e Is Read as Exponential Notation

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When JavaScript handles numbers and strings together,

a string containing e is recognized as exponential notation.

    let str = '1e5';
    let num = 100000;

    str == num  => true

    str === num => false

    isNaN(str)  => false
  

'1e5' is 1 * 10 ^5

which is read as 100,000.

In exponential notation, e means

"ten to the power of".

JavaScript converts it to the number 100,000 without being asked.

    let str = 'test1e5';

    isNaN(str)  => true
  

As shown here,

an ordinary string that merely contains an e

is not automatically converted to exponential notation.

Conclusion

When converting a string containing e into a number,

check whether the string actually fits the exponential notation format!!!