During my years on Python development, I\'ve always been amazed at how much much much faster things become if you manage to rewrite that code that loops though your ndarray and
No, there are no technical reasons why a numpy-like package does not exist for Node.js and, more generally, JavaScript.
There are two main obstacles preventing Node.js and JavaScript from achieving more mind share in the data science and numeric computing communities.
The first obstacle is community. While the JavaScript community is huge, the subset of people within that community doing interesting things in numeric computing is small. Hence, if you want to do numeric computing in JavaScript and Node.js, finding resources to help you along the way can be hard, and it may feel like a lonely endeavor.
Next, the absence of comparable libraries (chicken and egg: libraries are needed to attract library authors and authors are needed to write good libraries). There are no technical reasons why libraries cannot be written in JavaScript or leverage Node.js (e.g., via native add-ons). I know, as I have written many numeric computing libraries in JavaScript. So while numeric computing is possible in JavaScript, the problem stems from an inability to attract developers having sufficient expertise and capable of putting in the time and effort needed to write high quality numeric computing implementations.
Regarding the specific language features mentioned in the OP:
My personal belief is that some form of numeric computing is inevitable in JavaScript and Node.js. The advantages (ubiquity, distribution, performance) and potential applications (edge computing, integrating machine learning, data visualization) are too strong of evolutionary forces not to support data science applications, at least at a basic level.
disclosure: I and others are currently working on a project (https://github.com/stdlib-js/stdlib) which aims to provide numeric computing facilities in JavaScript and Node.js.