# Binary Convert a binary number, represented as a string (e.g. '101010'), to its decimal equivalent using first principles. Implement binary to decimal conversion. Given a binary input string, your program should produce a decimal output. The program should handle invalid inputs. ## Note - Implement the conversion yourself. Do not use something else to perform the conversion for you. ## About Binary (Base-2) Decimal is a base-10 system. A number 23 in base 10 notation can be understood as a linear combination of powers of 10: - The rightmost digit gets multiplied by 10^0 = 1 - The next number gets multiplied by 10^1 = 10 - ... - The *n*th number gets multiplied by 10^*(n-1)*. - All these values are summed. So: `23 => 2*10^1 + 3*10^0 => 2*10 + 3*1 = 23 base 10` Binary is similar, but uses powers of 2 rather than powers of 10. So: `101 => 1*2^2 + 0*2^1 + 1*2^0 => 1*4 + 0*2 + 1*1 => 4 + 1 => 5 base 10`. ## Setup Go through the setup instructions for JavaScript to install the necessary dependencies: http://exercism.io/languages/javascript ## Making the Test Suite Pass Execute the tests with: jasmine .spec.js Replace `` with the name of the current exercise. E.g., to test the Hello World exercise: jasmine hello-world.spec.js In many test suites all but the first test have been skipped. Once you get a test passing, you can unskip the next one by changing `xit` to `it`. ## Source All of Computer Science [http://www.wolframalpha.com/input/?i=binary&a=*C.binary-_*MathWorld-](http://www.wolframalpha.com/input/?i=binary&a=*C.binary-_*MathWorld-) ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.