PascalCase converter

PascalCase is named after the Pascal language and is sometimes called upper camel case, which describes it exactly. What it is used for is more specific than camelCase: types. Classes, interfaces, enums, structs and React components are PascalCase in almost every language that has a convention at all, and the reason is that it makes a type visually distinct from a variable of that type — User user reads unambiguously in a way user user would not.

In React the convention is enforced rather than advisory. JSX treats a lowercase tag as an HTML element and a capitalised one as a component, so <myButton /> renders a literal unknown element and <MyButton /> renders your component. That is a real bug with no error message, and it is the most common reason a React component silently fails to appear.

Go uses the first letter for visibility instead: a PascalCase name is exported from its package and a camelCase one is private. There is no public keyword — the capital letter is the keyword. Renaming a field from Name to name makes it invisible outside the package and, more surprisingly, invisible to encoding/json, which is why a struct that suddenly serialises as {} usually has lowercase fields.