checkSchema syntax documentation - express-validator

Question

I would like to use the checkSchema method instead of what I am currently doing with all the checks on the post route in an array. The problem I have is I can't find good documentation on the syntax used in the object for each key. The doc page for schema validation (https://express-validator.github.io/docs/schema-validation.html) gives one example but no links to all the syntax that defines all the attributes you can use (isInt, toInt, isUppercase, rtrim, etc.) I have searched high and low for the docs that tell you everything you can use there but no luck. Can someone point me in the right place?

Answer 1

express-validator is a set of express.js middlewares that wraps validator.js validator and sanitizer functions.
you can find all the rules available in the link above.
here is a good example how it's used with checkSchema:
import { checkSchema, validationResult } from 'express-validator'
const schema = {
id: {
isFloat: true,
// Sanitizers can go here as well
toFloat: true,
errorMessage: "must be a valid number"
},
first_name: {
exists: {
errorMessage: "first_name is required"
},
isLength: {
errorMessage: "first_name has invalid length",
options: {
min: 1
}
}
},
middle_name: {
optional: {
options: { nullable: true, checkFalsy: true }
}
},
last_name: {
exists: {
errorMessage: "last_name is required"
},
isLength: {
errorMessage: "last_name has invalid length",
options: {
min: 1
}
}
},
date_of_birth: {
isISO8601: {
errorMessage: `date of birth is not a valid iso date`
},
isBefore: {
date: "01-01-2000",
errorMessage: `should be less than 01-01-2000`
},
isAfter: {
date: "01-01-1970",
errorMessage: `should be greater than 01-01-1970`
}
},
email: {
exists: {
errorMessage: "email is required"
},
isEmail: {
errorMessage: "email is invalid"
}
},
current_country_of_residence: {
exists: {
errorMessage: "current_country_of_residence is required",
options: {
checkNull: true,
checkFalsy: true
}
}
},
current_city_of_residence: {
exists: {
bail: true,
errorMessage: "current_city_of_residence is required"
},
isMongoId: {
errorMessage: "current_city_of_residence is has invalid id for"
}
},
email: {
isEmail: { errorMessage: 'email is not a valid email' },
isLength: { errorMessage: 'email has invalid length', options: { min: 1 } }
},
skills: {
isArray: {
errorMessage: `invalid value for skills`,
options: {
min: 3,
max: 5
}
},
isIn: {
options: ["java", "C++", "javascript"],
errorMessage: `allowed values for skills are: ${["java", "C++", "javascript"]}`
},
custom: {
options: (values) => {
const unique_values = new Set(values)
if (unique_values.size !== values.length) {
return Promise.reject()
}
return Promise.resolve()
},
errorMessage: `you can't add duplicated`
},
customSanitizer: {
options: async (value, { req }) => {
return value
}
}
}
}
const validate = () => {
return [
checkSchema(schema),
(req, res, next) => {
const errors = validationResult(req)
if (!errors.isEmpty()) {
return res.status(422).json({ errors: errors.mapped() })
}
next()
}
]
}
export default validate()