This is a huge mistake if applied without care. Building things from scratch necessarily will introduce more bugs, more maintenance costs and leave you with a codebase that suffers from a lack of maturity.
Building things from scratch necessarily will introduce more bugs, more maintenance costs and leave you with a codebase that suffers from a lack of maturity.
Unfortunately, in some programming language ecosystems where having many small and transitive dependencies on modules from an non-curated repository is common, none of those three things is necessarily true.
Code reuse is not a trivial problem, and you always have to weigh the benefits against the costs and risks to decide whether it’s worth it. If we’re depending on GitHub repositories with a dozen files and three subdirectories just to provide some simple functionality that any junior programmer could implement directly in five lines of code, we’ve probably lost the plot. On the other hand, if we have a full in-house implementation of encryption algorithms we use to throw sensitive customer data around between the browser and our servers, we’ve also probably lost the plot.
I don't think the sentiment is 'implement everything from scratch', but rather that if something exists natively try to use that instead of pulling in other dependencies, like in the http client example.
Unfortunately, in some programming language ecosystems where having many small and transitive dependencies on modules from an non-curated repository is common, none of those three things is necessarily true.
Code reuse is not a trivial problem, and you always have to weigh the benefits against the costs and risks to decide whether it’s worth it. If we’re depending on GitHub repositories with a dozen files and three subdirectories just to provide some simple functionality that any junior programmer could implement directly in five lines of code, we’ve probably lost the plot. On the other hand, if we have a full in-house implementation of encryption algorithms we use to throw sensitive customer data around between the browser and our servers, we’ve also probably lost the plot.