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Version: 5.3.0

Schema Validation

Schemas are a special, object-based way of defining validations or sanitizations on requests.
At the root-level, you specify the field paths as the keys, and an object as values -- which define the error messages, locations and validations/sanitizations.

Its syntaxs looks like this:

const { checkSchema } = require('express-validator/check');
app.put('/user/:id/password', checkSchema({
id: {
// The location of the field, can be one or more of body, cookies, headers, params or query.
// If omitted, all request locations will be checked
in: ['params', 'query'],
errorMessage: 'ID is wrong',
isInt: true,
// Sanitizers can go here as well
toInt: true
},
myCustomField: {
// Custom validators
custom: {
options: (value, { req, location, path }) => {
return value + req.body.foo + location + path;
}
},
// and sanitizers
customSanitizer: {
options: (value, { req, location, path }) => {
let sanitizedValue;

if (req.body.foo && location && path) {
sanitizedValue = parseInt(value);
} else {
sanitizedValue = 0;
}

return sanitizedValue;
}
},
},
password: {
isLength: {
errorMessage: 'Password should be at least 7 chars long',
// Multiple options would be expressed as an array
options: { min: 7 }
}
},
firstName: {
isUppercase: {
// To negate a validator
negated: true,
},
rtrim: {
// Options as an array
options: [' -'],
},
},
// Wildcards/dots for nested fields work as well
'addresses.*.postalCode': {
optional: true,
isPostalCode: true
}
}), (req, res, next) => {
// handle the request as usual
})