validate form asynchronous
Validate form asynchronous. A variation of https://github.com/freeformsystems/async-validate
npm i async-validator
Basic usage involves defining a descriptor, assigning it to a schema and passing the object to be validated and a callback function to the
validatemethod of the schema:
import Schema from 'async-validator'; const descriptor = { name: { type: 'string', required: true, validator: (rule, value) => value === 'muji', }, age: { type: 'number', asyncValidator: (rule, value) => { return new Promise((resolve, reject) => { if (value < 18) { reject('too young'); // reject with error message } else { resolve(); } }); }, }, }; const 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', age: 16 }).then(() => { // validation passed or without error message }).catch(({ errors, fields }) => { return handleErrors(errors, fields); });
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 passed *
catch({ errors, fields }),validation failed, errors is an array of all errors, fields is an object keyed by field name with an array of
suppressWarning: Boolean, whether to suppress internal warning about invalid value.
first: Boolean, Invoke
callbackwhen 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[], Invoke
callbackwhen the first validation rule of the specified field generates an error, no more validation rules of the same field are processed.
truemeans all fields.
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 a
fieldproperty 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 of
Errorinstances to indicate validation failure. If the check is synchronous, you can directly return a
falseor
Erroror
Error Array.
source: The source object that was passed to the
validatemethod.
options: Additional options.
options.messages: The object containing validation error messages, will be deep merged with defaultMessages.
The options passed to
validateor
asyncValidateare 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,
exceptionand
error.
import Schema from 'async-validator'; const descriptor = { name(rule, value, callback, source, options) { const errors = []; if (!/^[a-z0-9]+$/.test(value)) { errors.push(new Error( util.format('%s must be lowercase alphanumeric characters', rule.field), )); } return errors; }, }; const 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:
const descriptor = { email: [ { type: 'string', required: true, pattern: Schema.pattern.email }, { validator(rule, value, callback, source, options) { const errors = []; // test if email address already exists in a database // and add a validation error to the errors array if it does return errors; }, }, ], };
Indicates the
typeof validator to use. Recognised type values are:
string: Must be of type
string.
This is the default type.
number: Must be of type
number.
boolean: Must be of type
boolean.
method: Must be of type
function.
regexp: Must be an instance of
RegExpor a string that does not generate an exception when creating a new
RegExp.
integer: Must be of type
numberand an integer.
float: Must be of type
numberand a floating point number.
array: Must be an array as determined by
Array.isArray.
object: Must be of type
objectand not
Array.isArray.
enum: Value must exist in the
enum.
date: Value must be valid as determined by
Date
url: Must be of type
url.
hex: Must be of type
hex.
any: Can be any type.
The
requiredrule property indicates that the field must exist on the source object being validated.
The
patternrule property indicates a regular expression that the value must match to pass validation.
A range is defined using the
minand
maxproperties. For
stringand
arraytypes comparison is performed against the
length, for
numbertypes the number must not be less than
minnor greater than
max.
To validate an exact length of a field specify the
lenproperty. For
stringand
arraytypes comparison is performed on the
lengthproperty, for the
numbertype this property indicates an exact match for the
number, ie, it may only be strictly equal to
len.
If the
lenproperty is combined with the
minand
maxrange properties,
lentakes precedence.
Since version 3.0.0 if you want to validate the values
0orfalseinsideenumtypes, you have to include them explicitly.
To validate a value from a list of possible values use the
enumtype with a
enumproperty listing the valid values for the field, for example:
const descriptor = { role: { type: 'enum', enum: ['admin', 'user', 'guest'] }, };
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
whitespaceproperty to a rule with a value of
true. The rule must be a
stringtype.
You may wish to sanitize user input instead of testing for whitespace, see transform for an example that would allow you to strip whitespace.
If you need to validate deep object properties you may do so for validation rules that are of the
objector
arraytype by assigning nested rules to a
fieldsproperty of the rule.
const 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 }, }; const 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
requiredproperty 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
optionspassed to the
schema.validate()method.
const descriptor = { address: { type: 'object', required: true, options: { 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 }, }; const 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:
const 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.
The
defaultFieldproperty can be used with the
arrayor
objecttype for validating all values of the container. It may be an
objector
arraycontaining validation rules. For example:
const descriptor = { urls: { type: 'array', required: true, defaultField: { type: 'url' }, }, };
Note that
defaultFieldis expanded to
fields, see deep rules.
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
transformfunction 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'; const descriptor = { name: { type: 'string', required: true, pattern: /^[a-z]+$/, transform(value) { return value.trim(); }, }, }; const validator = new Schema(descriptor); const source = { name: ' user ' }; validator.validate(source) .then(() => assert.equal(source.name, 'user'));
Without the
transformfunction 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.
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
messageto 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: 'Name is required' } }
Message can also be a function, e.g. if you use vue-i18n:
js { 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'; const cn = { required: '%s 必填', }; const descriptor = { name: { type: 'string', required: true } }; const 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.messagesproperty within the validation function.
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, }); }, }, };
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'), ]; }, }, };
import Schema from 'async-validator'; Schema.warning = function(){};
true
Use
enumtype passing
trueas option.
{ type: 'enum', enum: [true], message: '', }
npm test
npm run coverage
Open coverage/ dir
Everything is MIT.