I've never done it with JS. It's not really a problem in C, though. If there's a lot of data, you're no better off with text; if there's not much, reading binary data isn't too bad. You've usually got other problems on top of decoding the actual data - like, why is this data coming in the first place? Why isn't the code accepting it properly? Why isn't the other end listening? The data encoding is just the tip of the iceberg.

Either way, the advantages of binary often outweigh the difficulty of having a human read the data. As the saying goes, code is executed far more often than it's read.

(Most binary formats have some fairly obvious possible text representations, at least for key fields (they're just encoding ints, floats, strings, bitfields, etc.). When you're having difficulty, or you're simply curious, you can print them out. If the format is any good, malformed messages are easy to check for in code - this code is not harder to debug than any other. If anything it's actually easier than with some kind of text format.)