const Ajv = require('ajv@6.10.2');
const ajv = new Ajv;
const schema = {
"type": "object",
"properties": {
"hasA": { type: 'boolean' }
},
"required": ["hasA"]
};
const schema2 = {
"properties": {
"hasA": { type: 'boolean' }
},
"required": ["hasA"]
};
const data = undefined;
const validate = ajv.compile(schema);
const validate2 = ajv.compile(schema2);
console.log('First validation', validate(data), validate.errors);
console.log('Second validation', validate2(data), validate2.errors);