const ajv = new Ajv()
const validate = ajv.addSchema(defsSchema).compile(schema)
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token punctuation">(</span>alias<span class="token punctuation">)</span> <span class="token keyword">class</span> <span class="token class-name">ajv</span>
<span class="token keyword">import</span> ajv
<span class="token keyword">const</span> ajv<span class="token operator">:</span> Ajv</code></pre>

const ajv = new Ajv({loadSchema: loadSchema})

ajv.compileAsync(schema).then(function (validate) {
  const valid = validate(data)
  // ...
})

async function loadSchema(uri) {
  const res = await request.json(uri)
  if (res.statusCode >= 400) throw new Error("Loading error: " + res.statusCode)
  return res.body
}
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token punctuation">(</span>alias<span class="token punctuation">)</span> <span class="token keyword">class</span> <span class="token class-name">ajv</span>
<span class="token keyword">import</span> ajv
<span class="token keyword">const</span> ajv<span class="token operator">:</span> Ajv</code></pre>

const Ajv = require("ajv") // version >= v7.0.0
const ajv = new Ajv({code: {source: true}}) // this option is required to generate standalone code
const standaloneCode = require("ajv/dist/standalone").default

const schema = {
  $id: "https://example.com/object.json",
  type: "object",
  properties: {
    foo: {
      type: "string",
      pattern: "^[a-z]+$",
    },
  },
}

// 1. generate module with a single default export (CommonJS and ESM compatible):
const validate = ajv.compile(schema)
let moduleCode = standaloneCode(ajv, validate)

// 2. pass map of schema IDs to generate multiple exports,
// it avoids code duplication if schemas are mutually recursive or have some share elements:
let moduleCode = standaloneCode(ajv, {
  validateObject: "https://example.com/object.json",
})

// 3. or generate module with all schemas added to the instance (excluding meta-schemas),
// export names would use schema IDs (or keys passed to addSchema method):
let moduleCode = standaloneCode(ajv)

// now you can
// write module code to file
const fs = require("fs")
const path = require("path")
fs.writeFileSync(path.join(__dirname, "/validate.js"), moduleCode)

// ... or require module from string
const requireFromString = require("require-from-string")
const standaloneValidate = requireFromString(moduleCode) // for a single default export
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token keyword">import</span> Ajv</code></pre>

ajv.addKeyword({
  keyword: "range",
  type: "number",
  compile([min, max], parentSchema) {
    return parentSchema.exclusiveRange === true
      ? (data) => data > min && data < max
      : (data) => data >= min && data <= max
  },
  errors: false,
  metaSchema: {
    // schema to validate keyword value
    type: "array",
    items: [{type: "number"}, {type: "number"}],
    minItems: 2,
    additionalItems: false,
  },
})

const schema = {
  range: [2, 4],
  exclusiveRange: true,
}
const validate = ajv.compile(schema)
console.log(validate(2.01)) // true
console.log(validate(3.99)) // true
console.log(validate(2)) // false
console.log(validate(4)) // false
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token punctuation">(</span>alias<span class="token punctuation">)</span> <span class="token keyword">class</span> <span class="token class-name">ajv</span>
<span class="token keyword">import</span> ajv</code></pre>

const ajv = new Ajv({useDefaults: true})
const schema = {
  type: "object",
  properties: {
    foo: {type: "number"},
    bar: {type: "string", default: "baz"},
  },
  required: ["foo", "bar"],
}

const data = {foo: 1}

const validate = ajv.compile(schema)

console.log(validate(data)) // true
console.log(data) // { "foo": 1, "bar": "baz" }
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token punctuation">(</span>alias<span class="token punctuation">)</span> <span class="token keyword">class</span> <span class="token class-name">ajv</span>
<span class="token keyword">import</span> ajv
<span class="token keyword">const</span> ajv<span class="token operator">:</span> Ajv</code></pre>

const ajv = new Ajv({removeAdditional: true})
const schema = {
  additionalProperties: false,
  properties: {
    foo: {type: "number"},
    bar: {
      additionalProperties: {type: "number"},
      properties: {
        baz: {type: "string"},
      },
    },
  },
}

const data = {
  foo: 0,
  additional1: 1, // will be removed; `additionalProperties` == false
  bar: {
    baz: "abc",
    additional2: 2, // will NOT be removed; `additionalProperties` != false
  },
}

const validate = ajv.compile(schema)

console.log(validate(data)) // true
console.log(data) // { "foo": 0, "bar": { "baz": "abc", "additional2": 2 }
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token punctuation">(</span>alias<span class="token punctuation">)</span> <span class="token keyword">class</span> <span class="token class-name">ajv</span>
<span class="token keyword">import</span> ajv
<span class="token keyword">const</span> ajv<span class="token operator">:</span> Ajv</code></pre>

const ajv = new Ajv({coerceTypes: "array"})
const schema = {
  properties: {
    foo: {type: "array", items: {type: "number"}},
    bar: {type: "boolean"},
  },
}

const data = {foo: "1", bar: ["false"]}

const validate = ajv.compile(schema)

console.log(validate(data)) // true
console.log(data) // { "foo": [1], "bar": false }
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token punctuation">(</span>alias<span class="token punctuation">)</span> <span class="token keyword">class</span> <span class="token class-name">ajv</span>
<span class="token keyword">import</span> ajv
<span class="token keyword">const</span> ajv<span class="token operator">:</span> Ajv</code></pre>

function (resolve, reject) {
		if (!payload) {
			
			//...
} else {
			try {
				
				//...
if (valid && !validate.errors) {
					
					//...
} else {
					let message = ajv.errorsText(validate.errors);
					reject(new error.InternalValidationError(message));
				}

			} catch (err) {
				
				//...
}

		}

	}
<pre class="typing-tooltip"><code data-language="javascript" class="language-javascript"><span class="token punctuation">(</span>parameter<span class="token punctuation">)</span> <span class="token function-variable function">resolve</span><span class="token operator">:</span> <span class="token punctuation">(</span><span class="token parameter">value<span class="token operator">:</span> any</span><span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token keyword">void</span></code></pre>