Node.js 'Type Stripping' for TypeScript Now Enabled by Default
The JavaScript runtime Node.js can execute TypeScript (Microsoft's JavaScript-derived language with static typing). But now it can do it even better, explains Marco Ippolito of the Node.js steering committee: In August 2024 Node.js introduced a new experimental feature, Type Stripping, aimed at addressing a longstanding challenge in the Node.js ecosystem: running TypeScript with no configuration. Enabled by default in Node.js v23.6.0, this feature is on its way to becoming stable. TypeScript has reached incredible levels of popularity and has been the most requested feature in all the latest Node.js surveys. Unlike other alternatives such as CoffeeScript or Flow, which never gained similar traction, TypeScript has become a cornerstone of modern development. While it has been supported in Node.js for some time through loaders, they relied heavily on configuration and user libraries. This reliance led to inconsistencies between different loaders, making them difficult to use interchangeably. The developer experience suffered due to these inconsistencies and the extra setup required... The goal is to make development faster and simpler, eliminating the overhead of configuration while maintaining the flexibility that developers expect... TypeScript is not just a language, it also relies on a toolchain to implement its features. The primary tool for this purpose is tsc, the TypeScript compiler CLI... Type checking is tightly coupled to the implementation of tsc, as there is no formal specification for how the language's type system should behave. This lack of a specification means that the behavior of tsc is effectively the definition of TypeScript's type system. tsc does not follow semantic versioning, so even minor updates can introduce changes to type checking that may break existing code. Transpilation, on the other hand, is a more stable process. It involves converting TypeScript code into JavaScript by removing types, transforming certain syntax constructs, and optionally "downleveling" the JavaScript to allow modern syntax to execute on older JavaScript engines. Unlike type checking, transpilation is less likely to change in breaking ways across versions of tsc. The likelihood of breaking changes is further reduced when we only consider the minimum transpilation needed to make the TypeScript code executable — and exclude downleveling of new JavaScript features not yet available in the JavaScript engine but available in TypeScript... Node.js, before enabling it by default, introduced --experimental-strip-types. This mode allows running TypeScript files by simply stripping inline types without performing type checking or any other code transformation. This minimal technique is known as Type Stripping. By excluding type checking and traditional transpilation, the more unstable aspects of TypeScript, Node.js reduces the risk of instability and mostly sidesteps the need to track minor TypeScript updates. Moreover, this solution does not require any configuration in order to execute code... Node.js eliminates the need for source maps by replacing the removed syntax with blank spaces, ensuring that the original locations of the code and structure remain intact. It is transparent — the code that runs is the code the author wrote, minus the types... "As this experimental feature evolves, the Node.js team will continue collaborating with the TypeScript team and the community to refine its behavior and reduce friction. You can check the roadmap for practical next steps..." Read more of this story at Slashdot.
The JavaScript runtime Node.js can execute TypeScript (Microsoft's JavaScript-derived language with static typing).
But now it can do it even better, explains Marco Ippolito of the Node.js steering committee:
In August 2024 Node.js introduced a new experimental feature, Type Stripping, aimed at addressing a longstanding challenge in the Node.js ecosystem: running TypeScript with no configuration. Enabled by default in Node.js v23.6.0, this feature is on its way to becoming stable.
TypeScript has reached incredible levels of popularity and has been the most requested feature in all the latest Node.js surveys. Unlike other alternatives such as CoffeeScript or Flow, which never gained similar traction, TypeScript has become a cornerstone of modern development. While it has been supported in Node.js for some time through loaders, they relied heavily on configuration and user libraries. This reliance led to inconsistencies between different loaders, making them difficult to use interchangeably. The developer experience suffered due to these inconsistencies and the extra setup required... The goal is to make development faster and simpler, eliminating the overhead of configuration while maintaining the flexibility that developers expect...
TypeScript is not just a language, it also relies on a toolchain to implement its features. The primary tool for this purpose is tsc, the TypeScript compiler CLI... Type checking is tightly coupled to the implementation of tsc, as there is no formal specification for how the language's type system should behave. This lack of a specification means that the behavior of tsc is effectively the definition of TypeScript's type system. tsc does not follow semantic versioning, so even minor updates can introduce changes to type checking that may break existing code. Transpilation, on the other hand, is a more stable process. It involves converting TypeScript code into JavaScript by removing types, transforming certain syntax constructs, and optionally "downleveling" the JavaScript to allow modern syntax to execute on older JavaScript engines. Unlike type checking, transpilation is less likely to change in breaking ways across versions of tsc. The likelihood of breaking changes is further reduced when we only consider the minimum transpilation needed to make the TypeScript code executable — and exclude downleveling of new JavaScript features not yet available in the JavaScript engine but available in TypeScript...
Node.js, before enabling it by default, introduced --experimental-strip-types. This mode allows running TypeScript files by simply stripping inline types without performing type checking or any other code transformation. This minimal technique is known as Type Stripping. By excluding type checking and traditional transpilation, the more unstable aspects of TypeScript, Node.js reduces the risk of instability and mostly sidesteps the need to track minor TypeScript updates. Moreover, this solution does not require any configuration in order to execute code... Node.js eliminates the need for source maps by replacing the removed syntax with blank spaces, ensuring that the original locations of the code and structure remain intact. It is transparent — the code that runs is the code the author wrote, minus the types...
"As this experimental feature evolves, the Node.js team will continue collaborating with the TypeScript team and the community to refine its behavior and reduce friction. You can check the roadmap for practical next steps..."
Read more of this story at Slashdot.
