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update readme and request, response toJSON method update readme update readme update readme update readme update readme update readme update docs update doc pretty readme update docs fix then callback
49 lines
2 KiB
Markdown
49 lines
2 KiB
Markdown
# Frequently Asked Questions
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## Does Koa replace Express?
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It's more like Connect, but a lot of the Express goodies
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were moved to the middleware level in Koa to help form
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a stronger foundation. This makes middleware more enjoyable
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and less error-prone to write, for the entire stack, not
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just the end application code.
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Typically many middleware would
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re-implement similar features, or even worse incorrectly implement them,
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when features like signed cookie secrets among others are typically application-specific,
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not middleware specific.
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## Does Koa replace Connect?
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No, just a different take on similar functionality
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now that async functions allow us to write code with less
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callbacks. Connect is equally capable, and some may still prefer it,
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it's up to what you prefer.
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## Does Koa include routing?
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No - out of the box Koa has no form of routing, however
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many routing middleware are available: https://github.com/koajs/koa/wiki
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## Why isn't Koa just Express 4.0?
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Koa is a pretty large departure from what people know about Express,
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the design is fundamentally much different, so the migration from
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Express 3.0 to this Express 4.0 would effectively mean rewriting
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the entire application, so we thought it would be more appropriate
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to create a new library.
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## What custom properties do the Koa objects have?
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Koa uses its own custom objects: `ctx`, `ctx.request`, and `ctx.response`.
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These objects abstract node's `req` and `res` objects with convenience methods and getters/setters.
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Generally, properties added to these objects must obey the following rules:
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- They must be either very commonly used and/or must do something useful
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- If a property exists as a setter, then it will also exist as a getter, but not vice versa
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Many of `ctx.request` and `ctx.response`'s properties are delegated to `ctx`.
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If it's a getter/setter, then both the getter and the setter will strictly
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correspond to either `ctx.request` or `ctx.response`.
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Please think about these rules before suggesting additional properties.
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