Filtrex-interpolated

Interpolate a string with filtrex expressions

Supports custom functions, custom getProperty function, custom tag functions and validation function

Examples

String Interpolation

``js
import Interpolated from 'filtrex-interpolated'

const interpolated = new Interpolated('I am {age}')({age: 52})
expect(interpolated).toBe('I am 52')
`

String expression

`js
import Interpolated from 'filtrex-interpolated'

const interpolated = new Interpolated('{age}')({age: 52})
expect(interpolated).toBe(52) // NOTE: type is Number and not String
`

Custom function (second argument to filtrex)

`js
import Interpolated from 'filtrex-interpolated'
import {get} from 'lodash/object'

const scope = {
users: [
{name: 'U0'},
{name: 'U1'},
{name: 'U2'}
],
userIndex: 1
}
const compiled = new Interpolated('Welcome {get(users, userIndex, "name")}', {
custom: {
get: (src, ...path) => get(src, path)
}
})
expect(compiled(scope)).toBe('Welcome U1')
`

Using custom getProperty function (3rd argument to filtrex)

`js
class Name {
constructor(first, last) {
this.first = first
this.last = last
}

get full() {
return this.first + ' ' + this.last
}
}

function getProperty(propertyName, get, object) {
return (object instanceof Name) && propertyName === 'full' ? object[propertyName] : get(propertyName)
}
const interpolated4 = new Interpolated('{full of name}', { getProperty })({ name: new Name('FIRST', 'LAST') })
expect(interpolated4).toBe('FIRST LAST')
`

Using custom tag function

`js
// import tag -> the default tag function
import Interpolated, { tag } from 'filtrex-interpolated'

const interpolated1 = new Interpolated(
'collection/{id of doc}',
{
tag: (strings, ...values) => tag(strings, ...values)
}
)({})
expect(interpolated1).toBe('collection/')
`

Using validation function

`js
// import validate -> a tag factory that takes a custom validation function as argument
// The custom validation function is called for every expression value and must return an array with 2 elements
// [
// boolean: true when validation for value was successful,
// any: interpolation value to return when validation failed
// ]
// The validation function receives the following arguments:
// validate(value, index, values, strings)
// - value: value of the current expression
// - index: index of the current expression in values array
// - values: all expression values
// - strings: all strings
import Interpolated, { tag, validate } from 'filtrex-interpolated'

const interpolated1 = new Interpolated(
'collection/{id}',
{
tag: validate(value => [value !== undefined, undefined])
}
)({})
// validation failed -> interpolated value = second element in array returned from validate function
expect(interpolated1).toBe(undefined)

const interpolated2 = new Interpolated(
'collection/{id}',
{
tag: validate(value => [value !== undefined, undefined])
}
)({
id: 'my-id'
})
// validation success -> second element in array returned from validate function is ignored
expect(interpolated2).toBe('collection/my-id')

`

Changing interpolation regexp

`js
import Interpolated from 'filtrex-interpolated'
Interpolated.INTERPOLATE_REGEXP = /\$\{([^\}]+)\}/g
const interpolated = new Interpolated('${age}')({age: 52})
expect(interpolated).toBe(52)
``