Parsed body field validation middleware for Koa. This is a work in progress.
npm install --save koa-field-validate
See example.js in the root of this repository for a full example of usage.
The middleware provides a validate function on the app context, which takes a field name as an argument. The function will return an instance of a FieldValidator that exposes several validation methods that can be chained. Invalidations will be populated into the app context's fieldErrors object, where they will be keyed by field name. Handling of the existence of this.fieldErrors is up to the developer's discretion.
app.use(function *() {
// Perform validation on the required username field
this.validate('username').required();
this.validate('email').required().notEmpty().email();
// Assert that this.fieldErrors does not exist, throwing 400 if it does
this.assert(!this.fieldErrors, 400, { fields: this.fieldErrors });
// If the assertion was true, we have no errors
this.body = 'No errors!';
});This is still a very raw middleware and is in an alpha development phase. More validations will come.
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required(message) The field must exist.
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notEmpty(message) The field must not be empty.
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email(message) The field must match a valid email regex.