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Node Security by Dominic Barnes

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ES5 features

ECMAScript5 included an extensive batch of changes to JavaScript, including the following changes:

  1. Strict mode for removing unsafe features from the language.
  2. Property descriptors that give you control over object and property access.
  3. Functions for changing object mutability.

Strict mode

Strict mode changes the way JavaScript code runs in select cases. First, it causes errors to be thrown in cases that were silent before. Second, it removes and/or change features that made optimizations for JavaScript engines either difficult or impossible. Lastly, it prohibits some syntax that is likely to show up in future versions of JavaScript.

Additionally, strict mode is opt-in only, and can be applied either globally or for an individual function ...

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