How to validate the items of an array with ajv? - validation

Question

I have my validator defined as follows
var abcSchemaValidator = {
"type": "object",
"required": [],
"properties": {
"remarks": {
"type": "string",
"maxLength": 2000
},
"comment": {
"type": "string",
"maxLength": 2000
}
}
};
In my code where I am applying these validations, I am doing something like this
modelObject.remarks = sometext;
modelObject.parent[0].comment
So when I run my ajv validation using the following code
let validate = ajv.compile(schema);
let validResult = validate(data);
The remarks is validated properly whereas the comment is not. I can see why the remarks is straightforward but I am not sure how to make the comment work. Should I change the comment to parent.comment in the schemaValidator? I tried changing to parent[0].comment but that didn't work.

Answer 1

Your schema doesn't define any rule for parent nor does it forbid additional properties. As is your schema is working as expected.
As far as I can tell, parent is:
A non-required but expected property of an object
An array of objects, each of which can have a comment property which schema is the same as remarks
First, let's define something we can re-use:
ajv.addSchema({
$id: 'defs.json',
definitions: {
userInput: {
type: 'string',
maxLength: 10
}
}
});
Then, let's use this common definitions to redefine remarks and define parent
const validate = ajv.compile({
$id: 'main.json',
type: 'object',
properties: {
remarks: {$ref: 'defs.json#/definitions/userInput'},
parent: {
type: 'array',
items: {
type: 'object',
properties: {
comment: {$ref: 'defs.json#/definitions/userInput'}
}
}
}
}
});
And now let's validate some data:
// OK
console.assert(validate({remarks: 'foo'}),
JSON.stringify(validate.errors, null, 2));
// ERR: `remarks` is too long
console.assert(validate({remarks: 'foobarbazbat'}),
JSON.stringify(validate.errors, null, 2));
// OK: schema doesn't say `parent` can't be empty
console.assert(validate({remarks: 'foo', parent: []}),
JSON.stringify(validate.errors, null, 2));
// OK: schema doesn't say `parent` elements MUST have a `comment` property
console.assert(validate({remarks: 'foo', parent: [{}]}),
JSON.stringify(validate.errors, null, 2));
// OK
console.assert(validate({remarks: 'foo', parent: [{comment: 'foo'}]}),
JSON.stringify(validate.errors, null, 2));
// ERR: `comment` is too long
console.assert(validate({remarks: 'foo', parent: [{comment: 'foobarbazbat'}]}),
JSON.stringify(validate.errors, null, 2));
<script src="https://cdnjs.cloudflare.com/ajax/libs/ajv/6.10.2/ajv.min.js"></script>
<script>
const ajv = new Ajv();
ajv.addSchema({
$id: 'defs.json',
definitions: {
userInput: {
type: 'string',
maxLength: 10
}
}
});
const validate = ajv.compile({
$id: 'main.json',
type: 'object',
properties: {
remarks: {$ref: 'defs.json#/definitions/userInput'},
parent: {
type: 'array',
items: {
type: 'object',
properties: {
comment: {$ref: 'defs.json#/definitions/userInput'}
}
}
}
}
});
</script>