Given a specific scope what is the easiest way to write various rules that be tested against the scope for various reasons
Useful for testing & validation Business Logic stored as json.
npm install rule-filter-validator
// Initial state/scope/payload
const SCOPE = {
person: {
id: 1,
dob: "1998-02-18",
age: 23,
active: true,
gender: 'F'
}
}// Validate and return errors
const rule: Filter = {
"person": {
"age": {
"_gt": 18,
"_lt": 25
}
}
}
let errors = validatePayload(rule, SCOPE);
return ! errors.length // true// Simply validate
// Using field alter functions
isValidPayload({ person: { 'year(dob)': { _eq: 1998 } } }, SCOPE) // true
// Using $NOW
isValidPayload({ person: { 'dob': { _gt: '$NOW(-6 years)' } } }, SCOPE) // falseView all methods and functions
NOTE: Strictness
By default tests are case and type insensitive, meaning:
| Rule | Fn | Scope | Result |
|---|---|---|---|
| 1 | _eq | '1' | true |
| 'ABC' | _eq | 'abc' | true |
| 'zxc3' | _contains | 3 | true |
| 'zxc3' | _contains | 'ZXC' | true |
Calling validatePayload(filter, payload, [strict = false]) with strict = true will make the validator to be case and type sensitive.
| Rule | Fn | Scope | Result |
|---|---|---|---|
| 1 | _eq | '1' | false |
| 'ABC' | _eq | 'abc' | false |
| 'zxc3' | _contains | 3 | true |
| 'zxc3' | _contains | 'ZXC' | false |
_contains always compares as strings and is therefore not type sensitive
Find a matching price rule
const prices = [
{
label: 'Child price'
price: 100,
logic: {
"person": {
"age": {
"_lt": 18
}
}
}
},
{
label: 'Adult price'
price: 200,
logic: {
"person": {
"age": {
"_gte": 18
}
}
}
}
]
const scope = getUserScope(); // You implement this.
const priceToPay = prices.find(({ price, logic }) => {
let e = validatePayload(logic, scope)
return ! e.length
})Matching items in a list
const filter: Filter = {
_or: [{
permissions: {
_$: {
action: {
_eq: 'update',
},
collection: {
_eq: 'membership',
},
fields: {
_contains: 'status',
},
},
},
},
{
role: {
_eq: 'admin',
},
}],
};
const scope = {
role: 'author',
permissions: [
{
action: 'create',
collection: 'membership',
fields: ['person', 'status'],
},
{
action: 'read',
collection: 'membership',
fields: ['id', 'person', 'status'],
},
{action: 'update', collection: 'membership', fields: ['status']},
],
};
const canAccess = validatePayload(filter, scope, strict?).length === 0Using functions and date adjustments
// passes
validatePayload(
{ person: {'year(dob)': {_eq: 2009}} },
{ person: { dob: '2009-02-18' } }
);
// passes (IF the year is currently 2021)
validatePayload(
{ person: {'year(dob)': {_eq: '$NOW(-12 years).year'}} },
{ person: { dob: '2009-02-19' } }
);-
isValidPayload(Filter, Payload, strict?)This is a simple function that returns true if the payload is valid against the filter, and false otherwise.
-
validatePayload(Filter, Payload, strict?)This is the main function that validates the payload against the filter. It returns an array of errors, if any.
-
invertFilter(Filter)Inverts the filter, so that the filter will return the opposite of what it would have returned before.
-
extractFieldFromFilter(Filter, Field, Path?)This extracts the given field from the passed Filter and returns a new Filter object that only contains only the given field and its children, if any.
-
adjustDate(date, adjustment)The function applies adjustments to the Date using built-in methods such as setUTCMonth, setUTCHours, etc., based on the type of adjustment requested. If no supported adjustment type is supplied, it returns undefined.
eg.
-1 monthwill return the date 1 month before the given date.Supports years, months, days, hours, minutes, seconds, milliseconds, and weeks.
Currently only supporting one dynamic value, which is $NOW.
Examples:
$NOW(-1 month)will test the payload with the date 1 month before the current date.$NOW(-12 years).yearwill test the payload with the year 12 years before the current date.
Supports all field functions that can be applied to a date.
| Fn | Description | Accepted Types |
|---|---|---|
| _and | All of the specified filters must be true for the expression to be true | array of filters |
| _or | At least one of the specified filters must be true for the expression to be true | array of filters |
| _$ | Used as an index for array of objects, whereby at least one item must pass the filter for the expression to be true. | object |
Used on fields to perform operations on them.
eg. year(dob) will test with the year of the date of birth.
| Fn | Description | Accepted Types |
|---|---|---|
| year() | the year of the date | date, isoString |
| month() | the month of the date | date, isoString |
| week() | the week of the date | date, isoString |
| day() | the day of the date | date, isoString |
| hour() | the hour of the date | date, isoString |
| minute() | the minute of the date | date, isoString |
| second() | the second of the date | date, isoString |
| count() | the number of items in the array | array |
| Fn | Description | Accepted Types |
|---|---|---|
| _eq | equal to | string, number, boolean |
| _neq | not equal to | string, number, boolean |
| _contains | string/array contains | string, number |
| _ncontains | string/array does not contain | string, number |
| _starts_with | starts with | string, number |
| _nstarts_with | does not start with | string, number |
| _ends_with | ends with | string, number |
| _nends_with | does not end with | string, number |
| _in | in | string, Array |
| _nin | not in | string, Array |
| _between | between | string, number, Date |
| _nbetween | not between | string, number, Date |
| _gt | greater than | string, number, Date |
| _gte | greater than or equal to | string, number, Date |
| _lt | less than | string, number, Date |
| _lte | less than or equal to | string, number, Date |
| _null | null = | string, number, boolean, Date, Array |
| _nnull | not null = | string, number, boolean, Date, Array |
| _empty | empty = | string, Array |
| _nempty | not empty = | string, Array |
| _submitted | submitted = | string, number, boolean, Date, Array |
| _regex | matching regex | string, number, boolean, Date |
Examples of using `_$`
Given the following data record:
const data = {
colors: [{
name: 'red',
hex: '#ff0000',
}, {
name: 'green',
hex: '#00ff00',
}, {
name: 'blue',
hex: '#0000ff',
}]
};The following filter will pass:
{
colors: {
_$: {
name: {
_eq: 'red',
},
},
},
}And the following will fail:
{
colors: {
_$: {
name: {
_eq: 'yellow',
},
},
},
}You could also have multiple properties that have to match
// Will pass
{
colors: {
_$: {
name: {
_eq: 'red',
},
hex: {
_eq: '#ff0000',
},
},
},
}
// Will fail
{
colors: {
_$: {
name: {
_eq: 'red',
},
hex: {
_eq: '#ff4444',
},
},
},
};