This article will introduce how to use leoric to constrain model’s attributes and validate its’ values.
The attribute definition of the model can set whether the attribute can be null or not. When the model is synchronized, the corresponding table’s field attribute characteristics (NOT NULL or NULL) will be generated according to the value of allowNull. When the model instance attribute value does not match the setting, an error will be thrown.
const { Bone, DataTypes } = require('leoric');
class User extends Bone {
static attributes = {
id: { type: DataTypes.BIGINT, primaryKey: true },
email: { type: DataTypes.STRING, allowNull: false },
...
}
};
User.sync();
/*
CREATE TABLE `users` (
`id` bigint(20) AUTO_INCREMENT PRIMARY KEY,
`email` varchar(256) NOT NULL,
....
);
*/
User.create({ name: 'OldHunter' }); // throw LeoricValidateError('notNull'); email should not be null
You can set a unique constraint on a field using ‘unique’:
const { Bone, DataTypes } = require('leoric');
class User extends Bone {
static attributes = {
id: { type: DataTypes.BIGINT, primaryKey: true },
email: { type: DataTypes.STRING, allowNull: false, unique: true },
...
}
};
User.sync();
/*
CREATE TABLE `users` (
`id` bigint(20) AUTO_INCREMENT PRIMARY KEY,
`email` varchar(256) NOT NULL UNIQUE,
....
);
*/
In addition to validators included in validator.js as built-in validators, leoric also provides the following built-in validators:
class User extends Bone {
static attributes = {
var: {
type: ANYTYPE,
validate: {
notIn: [['MHW', 'Bloodborne']], // Not one of them
notNull: true, // Can't be NULL
isNull: true, // Must be NULL
min: 1988, // MinValue
max: 2077, // MaxValue
contains: 'Handsome', // Must contains 'Handsome'
notContains: 'Handsome', // Mustn't contain 'Handsome'
regex: /^iceborne/g, // Matching RegExp
notRegex: /^iceborne/g, // Not matching RegExp
is: /^iceborne/g, // Matching RegExp
notEmpty: true, // not allow empty string
}
}
}
}
The built-in validator supports customize error messages instead of the default error messages of leoric.
class User extends Bone {
static attributes = {
var: {
type: ANYTYPE,
validate: {
isIn: {
args: [ 'MHW', 'Bloodborne' ], // 'args' are the arguments of validator
msg: 'OH! WHAT HAVE YOU DONE?!' // `msg` is custom error message
},
notNull: {
args: true,
msg: 'OH! WHAT HAVE YOU DONE?!'
}
}
}
}
}
leoric supports set custom validators. You can throw an error or return false from the validator while the validation fails, and Leoric will take the next step based on the returns.
class User extends Bone {
static attributes = {
desc: {
type: DataTypes.STRING,
validate: {
isValid() {
if (this.desc && this.desc.length < 2) { // you can access attribute's value by this
throw new Error('Invalid desc');
}
},
lengthMax(value) { // the first argument is the value of attribute
if (value && value.length >= 10) {
return false;
}
}
}
}
}
}