async-validator
Validate form asynchronous. A variation of https://github.com/freeformsystems/async-validate
API
The following is modified from earlier version of async-validate.
Usage
Basic usage involves defining a descriptor, assigning it to a schema and passing the object to be validated and a callback function to the validate
method of the schema:
import schema from 'async-validator';
var descriptor = {
name: {
type: "string",
required: true,
validator: (rule, value) => value === 'muji',
},
};
var validator = new schema(descriptor);
validator.validate({name: "muji"}, (errors, fields) => {
if(errors) {
// validation failed, errors is an array of all errors
// fields is an object keyed by field name with an array of
// errors per field
return handleErrors(errors, fields);
}
// validation passed
});
// PROMISE USAGE
validator.validate({
name: "muji",
asyncValidator: (rule, value) => axios.post('/nameValidator', { name: value }),
}, (errors, fields) => {
if(errors) {
// validation failed, errors is an array of all errors
// fields is an object keyed by field name with an array of
// errors per field
return handleErrors(errors, fields);
}
// validation passed
})
.then(() => {
// validation passed
})
.catch(({ errors, fields }) => {
return handleErrors(errors, fields);
})
Validate
function(source, [options], callback): Promise
source
: The object to validate (required).options
: An object describing processing options for the validation (optional).callback
: A callback function to invoke when validation completes (required).
The method will return a Promise object like:
then()
,validation passedcatch({ errors, fields })
,validation failed, errors is an array of all errors, fields is an object keyed by field name with an array of
Options
-
suppressWarning
: Boolean, whether to suppress internal warning about invalid value. -
first
: Boolean, Invokecallback
when the first validation rule generates an error, no more validation rules are processed. If your validation involves multiple asynchronous calls (for example, database queries) and you only need the first error use this option. -
firstFields
: Boolean|String[], Invokecallback
when the first validation rule of the specified field generates an error, no more validation rules of the same field are processed.true
means all fields.
Rules
Rules may be functions that perform validation.
function(rule, value, callback, source, options)
rule
: The validation rule in the source descriptor that corresponds to the field name being validated. It is always assigned afield
property with the name of the field being validated.value
: The value of the source object property being validated.callback
: A callback function to invoke once validation is complete. It expects to be passed an array ofError
instances to indicate validation failure. If the check is synchronous, you can directly return afalse
orError
orError Array
.source
: The source object that was passed to thevalidate
method.options
: Additional options.options.messages
: The object containing validation error messages, will be deep merged with defaultMessages.
The options passed to validate
or asyncValidate
are passed on to the validation functions so that you may reference transient data (such as model references) in validation functions. However, some option names are reserved; if you use these properties of the options object they are overwritten. The reserved properties are messages
, exception
and error
.
import schema from 'async-validator';
var descriptor = {
name(rule, value, callback, source, options) {
var errors = [];
if(!/^[a-z0-9]+$/.test(value)) {
errors.push(
new Error(
util.format("%s must be lowercase alphanumeric characters",
rule.field)));
}
return errors;
}
}
var validator = new schema(descriptor);
validator.validate({name: "Firstname"}, (errors, fields) => {
if(errors) {
return handleErrors(errors, fields);
}
// validation passed
});
It is often useful to test against multiple validation rules for a single field, to do so make the rule an array of objects, for example:
var descriptor = {
email: [
{type: "string", required: true, pattern: schema.pattern.email},
{validator(rule, value, callback, source, options) {
var errors = [];
// test if email address already exists in a database
// and add a validation error to the errors array if it does
return errors;
}}
]
}
Type
Indicates the type
of validator to use. Recognised type values are:
string
: Must be of typestring
.This is the default type.
number
: Must be of typenumber
.boolean
: Must be of typeboolean
.method
: Must be of typefunction
.regexp
: Must be an instance ofRegExp
or a string that does not generate an exception when creating a newRegExp
.integer
: Must be of typenumber
and an integer.float
: Must be of typenumber
and a floating point number.array
: Must be an array as determined byArray.isArray
.object
: Must be of typeobject
and notArray.isArray
.enum
: Value must exist in theenum
.date
: Value must be valid as determined byDate
url
: Must be of typeurl
.hex
: Must be of typehex
.email
: Must be of typeemail
.
Required
The required
rule property indicates that the field must exist on the source object being validated.
Pattern
The pattern
rule property indicates a regular expression that the value must match to pass validation.
Range
A range is defined using the min
and max
properties. For string
and array
types comparison is performed against the length
, for number
types the number must not be less than min
nor greater than max
.
Length
To validate an exact length of a field specify the len
property. For string
and array
types comparison is performed on the length
property, for the number
type this property indicates an exact match for the number
, ie, it may only be strictly equal to len
.
If the len
property is combined with the min
and max
range properties, len
takes precedence.
Enumerable
Since version 3.0.0 if you want to validate the values
0
orfalse
insideenum
types, you have to include them explicitly.
To validate a value from a list of possible values use the enum
type with a enum
property listing the valid values for the field, for example:
var descriptor = {
role: {type: "enum", enum: ['admin', 'user', 'guest']}
}
Whitespace
It is typical to treat required fields that only contain whitespace as errors. To add an additional test for a string that consists solely of whitespace add a whitespace
property to a rule with a value of true
. The rule must be a string
type.
You may wish to sanitize user input instead of testing for whitespace, see transform for an example that would allow you to strip whitespace.
Deep Rules
If you need to validate deep object properties you may do so for validation rules that are of the object
or array
type by assigning nested rules to a fields
property of the rule.
var descriptor = {
address: {
type: "object", required: true,
fields: {
street: {type: "string", required: true},
city: {type: "string", required: true},
zip: {type: "string", required: true, len: 8, message: "invalid zip"}
}
},
name: {type: "string", required: true}
}
var validator = new schema(descriptor);
validator.validate({ address: {} }, (errors, fields) => {
// errors for address.street, address.city, address.zip
});
Note that if you do not specify the required
property on the parent rule it is perfectly valid for the field not to be declared on the source object and the deep validation rules will not be executed as there is nothing to validate against.
Deep rule validation creates a schema for the nested rules so you can also specify the options
passed to the schema.validate()
method.
var descriptor = {
address: {
type: "object", required: true, options: {single: true, first: true},
fields: {
street: {type: "string", required: true},
city: {type: "string", required: true},
zip: {type: "string", required: true, len: 8, message: "invalid zip"}
}
},
name: {type: "string", required: true}
}
var validator = new schema(descriptor);
validator.validate({ address: {} })
.catch(({ errors, fields }) => {
// now only errors for street and name
});
The parent rule is also validated so if you have a set of rules such as:
var descriptor = {
roles: {
type: "array", required: true, len: 3,
fields: {
0: {type: "string", required: true},
1: {type: "string", required: true},
2: {type: "string", required: true}
}
}
}
And supply a source object of {roles: ["admin", "user"]}
then two errors will be created. One for the array length mismatch and one for the missing required array entry at index 2.
defaultField
The defaultField
property can be used with the array
or object
type for validating all values of the container.
It may be an object
or array
containing validation rules. For example:
var descriptor = {
urls: {
type: "array", required: true,
defaultField: {type: "url"}
}
}
Note that defaultField
is expanded to fields
, see deep rules.
Transform
Sometimes it is necessary to transform a value before validation, possibly to coerce the value or to sanitize it in some way. To do this add a transform
function to the validation rule. The property is transformed prior to validation and re-assigned to the source object to mutate the value of the property in place.
import schema from 'async-validator';
import { sanitize } from 'validator');
var descriptor = {
name: {
type: "string",
required: true, pattern: /^[a-z]+$/,
transform(value) {
return sanitize(value).trim();
}
}
}
var validator = new schema(descriptor);
var source = {name: " user "};
validator.validate(source)
.then(() => assert.equal(source.name, "user"));
Without the transform
function validation would fail due to the pattern not matching as the input contains leading and trailing whitespace, but by adding the transform function validation passes and the field value is sanitized at the same time.
Messages
Depending upon your application requirements, you may need i18n support or you may prefer different validation error messages.
The easiest way to achieve this is to assign a message
to a rule:
{name:{type: "string", required: true, message: "Name is required"}}
Message can be any type, such as jsx format.
{name:{type: "string", required: true, message: <b>Name is required</b>}}
Message can also be a function, e.g. if you use vue-i18n:
{name:{type: "string", required: true, message: () => this.$t( 'name is required' )}}
Potentially you may require the same schema validation rules for different languages, in which case duplicating the schema rules for each language does not make sense.
In this scenario you could just provide your own messages for the language and assign it to the schema:
import schema from 'async-validator';
var cn = {
required: '%s 必填',
};
var descriptor = {name:{type: "string", required: true}};
var validator = new schema(descriptor);
// deep merge with defaultMessages
validator.messages(cn);
...
If you are defining your own validation functions it is better practice to assign the message strings to a messages object and then access the messages via the options.messages
property within the validation function.
asyncValidator
You can customize the asynchronous validation function for the specified field:
const fields = {
asyncField:{
asyncValidator(rule,value,callback){
ajax({
url:'xx',
value:value
}).then(function(data){
callback();
},function(error){
callback(new Error(error))
});
}
},
promiseField:{
asyncValidator(rule, value){
return ajax({
url:'xx',
value:value
});
}
}
};
validator
you can custom validate function for specified field:
const fields = {
field:{
validator(rule,value,callback){
return value === 'test';
},
message: 'Value is not equal to "test".',
},
field2:{
validator(rule,value,callback){
return new Error(`'${value} is not equal to "test".'`);
},
},
arrField:{
validator(rule, value){
return [
new Error('Message 1'),
new Error('Message 2'),
];
}
},
};
FAQ
How to avoid warning
import Schema from 'async-validator';
Schema.warning = function(){};
true
How to check if it is Use enum
type passing true
as option.
{
type: 'enum',
enum: [true],
message: '',
}
Test Case
npm test
npm run chrome-test
Coverage
npm run coverage
open coverage/ dir
License
Everything is MIT.