When using Angular @NgModule imports, it is important to note that modules may not be recognized if the [].concat() method is

I am dealing with multiple modules and I need to organize and categorize them into different arrays based on their types

const firstModules: any[] = [
  Module1,
  Module2,
  Module3,
  Module4
];

const secondModules: any[] = [
  Module5,
  Module6,
  Module7,
  Module8
]

When using spread operator, everything works fine

imports: [Module0, ...firstModules, ...secondModules]

However, if I try to use the concat method instead, the components do not work as expected:

imports: [Module0].concat(firstModules, secondModules)

What is the difference for the TypeScript compiler between these two methods? At a glance,

console.log([Module0, ...firstModules, ...secondModules]);
console.log([Module0].concat(firstModules, secondModules));

Both results may seem identical, but they behave differently in practice.

Answer №1

Unfortunately, there isn't much documentation available to answer this question regarding the inner workings of the Angular compiler. The AOT compiler handles a significant amount of metadata transformation for decorators, and it may struggle with certain cases like this one.

This issue is specific to the AOT compiler itself and not related to TypeScript or JavaScript.

If you're interested in learning more about transformers in Angular, you can check out this blog post:

The source code for the transformers can be found here:

https://github.com/angular/angular/tree/master/packages/compiler-cli/src/transformers

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