ajv

• ajv-validator/ajv
  • JSON Schema 校验
  • 支持 JTD serialize/parse
    • 类似于 fastify/fast-json-stringify
• 参考
  • ajv-validator/ajv-keywords 增加自定义关键字
    • typeof, instanceof
    • select, selectCases, selectDefault -> discriminator
    • dynamicDefaults
    • number: range, exclusiveRange
    • string: regexp, transform
      • transform 允许验证时修改字符串内容
    • array: uniqueItemProperties
    • object: allRequired, anyRequired, oneRequired, patternRequired, prohibited, deepProperties, deepRequired
  • https://ajv.js.org/json-schema.html
  • https://validatejs.org/

caution

• additionalProperties 不能默认为 false
  • ajv-validator/ajv#634

npm add ajv ajv-formats ajv-keywords ajv-errors

import addFormats from 'ajv-formats';
import addKeywords from 'ajv-keywords';
import Ajv2020 from 'ajv/dist/2020';

const ajv = new Ajv2020();
addFormats(ajv);
addKeywords(ajv);

// 添加自定义 keyword 避免失败
ajv.addKeyword('x-meta');

format	example	description
ajv-formats
date	2021-01-01	RFC3339 full-date
time	14:30:00+01:00	time with optional time-zone.
date-time	2021-01-01T14:30:00+01:00	date-time from the same source (time-zone is mandatory).
duration	P3Y6M4DT12H30M5S	RFC3339 duration
uri	https://example.com	full URI.
uri-reference	/relative/uri	URI reference, including full and relative URIs.
uri-template	https://example.com/{user}	RFC6570 URI template
url	https://example.com	URL record
email	user@example.com	email address.
hostname	example.com	RFC1034 host name
ipv4	192.168.0.1	IPv4
ipv6	2001:0db8:85a3:0000:0000:8a2e:0370:7334	IPv6
regex	^[a-zA-Z0-9]+$	RegExp
uuid	123e4567-e89b-12d3-a456-426614174000	RFC4122 UUID
json-pointer	/pointer	RFC6901 JSON-pointer
relative-json-pointer	0	draft relative JSON-pointer
ajv-formats-draft2019
iri	https://例子.测试	RFC3987 IRN/Internationalized Resource Identifier
iri-reference	/relative/路径	IRI reference, including full and relative IRIs.
idn-hostname	例子.测试	RFC5890 IDN/Internationalized Domain Name hostname
idn-email	用户@例子.测试	RFC6531 Internationalized email address

// 自定义 format
ajv.addFormat('identifier', /^a-z\$_[a-zA-Z$_0-9]*$/);
// 使用自定义逻辑校验 format
ajv.addFormat('byte', {
  type: 'number',
  validate: (x) => x >= 0 && x <= 255 && x % 1 == 0,
});
ajv.addFormat('int8', {
  type: 'number',
  validate: (x) => x >= -128 && x <= 127 && Number.isInteger(x),
});

standalone validation code

• 生成独立的函数

npm install -g ajv-cli
ajv compile -s schema.json -o validate_schema.js

• https://ajv.js.org/standalone.html

addKeyword

• https://ajv.js.org/keywords.html

FAQ

due to error strict mode: unknown keyword

ajv schema with key or id already exists

• 如果 schema 有 $id 可能会出现
• 如果 schema 是通过反序列化生成的，可能会出现重复 - ref 不一样但 id 一样

strict mode: unknown keyword

未知关键字，需要添加关键字支持

修改校验数据

类似 zod.parse 能得到一个解析后的满足验证要求的对象，不过 zod 不会修改传入对象，ajv 只能通过修改传入对象实现，这一点上 ajv 性能更好

• 移除额外
• 添加 defaults
• 强制类型转换
• coerceTypes=true|'array'
  • array 支持 x <-> [x]

const ajv = new Ajv({ removeAdditional: true, useDefaults: true, coerceTypes: 'array' });

const schema = {
  type: 'object',
  additionalProperties: false,
  properties: {
    foo: { type: 'array', items: { type: 'number' } },
    bar: { type: 'boolean' },
    num: { type: 'number' },
    name: { type: 'string', default: 'wener' },
  },
};

const data = { foo: '1', bar: 'false', rm: true, num: '10' };

const validate = ajv.compile(schema);

// true
console.log(validate(data));
// {foo: [1], bar: false, num: 10, name: "wener"}
console.log(data);

• https://runkit.com/npm/ajv
• https://ajv.js.org/guide/modifying-data.html