Tree shaking can be leveraged by importing only the necessary components from the third-party library. This way, the bundler can exclude the unused parts during the build process, optimizing the bundle size. The other options are not efficient for tree shaking purposes.

The reduce method is used to execute a reducer function on each element of the array, resulting in a single output value.

Dynamic imports are especially useful for asynchronous loading of modules. Unlike traditional synchronous imports, dynamic imports allow modules to be loaded asynchronously, enabling the application to continue executing code without waiting for the module to be fully loaded. This asynchronous behavior is beneficial for optimizing performance, especially in scenarios where certain modules are only needed under specific conditions. Understanding the advantages of asynchronous module loading is crucial for developing efficient and responsive JavaScript applications.

The correct option is Properties. When using mixins in ES6, there can be conflicts between the properties of the mixin and the target class. It's important to handle these conflicts appropriately to ensure the correct behavior of the composed object.

ES6 supports dynamic property names through computed property names. By using square brackets around an expression within an object literal, you can create properties with names determined at runtime. This enhances the flexibility and expressiveness of object literals.

In-depth content in the explanation. ES6 introduces the concept of tail call optimization, allowing for deeper recursion without causing a stack overflow. Tail calls occur when a function's last action is a recursive call, and ES6 optimizes these tail calls to prevent excessive stack usage.

Unlike objects, where keys are converted to strings, a Map in JavaScript can have keys of any data type. So, the correct answer is string.

The correct option is 'block'. In JavaScript, a variable declared with 'let' has block-level scope. This means it can be redeclared within a different block, such as within a different if statement or loop. However, attempting to redeclare it in the same block or scope will result in an error.

The for...of loop is designed for iterating over iterable data structures, such as arrays and strings. It simplifies the process of iterating over the values without the need for index management.

In this scenario, the most suitable array method is filter. The filter method is designed for creating a new array containing elements that pass a certain condition. It allows you to filter out numbers greater than 10 effectively.