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Filters API

registerFilter

Register a custom filter callable from templates as {{ value|filter_name:arg }}.

const { registerFilter } = require('miki-template');



registerFilter('reverse', (val) => {

  return String(val).split('').reverse().join('');

});

import { registerFilter } from 'miki-template';



registerFilter('reverse', (val) => {

  return String(val).split('').reverse().join('');

});

Filter Signature

Filters receive (value, argument, context) and must return a string (or SafeString):

registerFilter('greet', (val, greeting, context) => {

  return `${greeting}, ${val}!`;

});

Async Filters

Filters that return a Promise are awaited automatically when using asyncRender():

const { registerFilter, asyncRender } = require('miki-template');



registerFilter('fetch_data', async (url) => {

  const res = await fetch(url);

  return res.text();

});



const html = await asyncRender('{{ endpoint|fetch_data }}', {

  endpoint: 'https://api.example.com/data'

});

import { registerFilter, asyncRender } from 'miki-template';



registerFilter('fetch_data', async (url) => {

  const res = await fetch(url);

  return res.text();

});



const html = await asyncRender('{{ endpoint|fetch_data }}', {

  endpoint: 'https://api.example.com/data'

});

getFilter

Retrieve a registered filter by name.

const { getFilter } = require('miki-template);



const reverseFilter = getFilter('reverse');

console.log(reverseFilter('hello')); // 'olleh'

import { getFilter } from 'miki-template';



const reverseFilter = getFilter('reverse');

Built-in Filters

Text Filters

| Filter | Description |

|--------|-------------|

| upper | Uppercase |

| lower | Lowercase |

| title | Title case |

| capfirst | Capitalize first character |

| truncatewords:N | Truncate to N words |

| truncatechars:N | Truncate to N characters (ellipsis) |

| truncatechars_html:N | Truncate to N chars, preserving HTML |

| wordcount | Count words |

| repeat | Repeat a string N times | | range | Generate a range of integers | | striptags | Remove HTML tags |

| slugify | Convert to URL-friendly slug |

| linebreaks | Convert newlines to <br> and <p> |

| linebreaksbr | Convert newlines to <br> |

| length_is:N | Return length if equals N, else empty |

HTML Filters

| Filter | Description |

|--------|-------------|

| safe | Mark as safe (no escaping) |

| escape | Force HTML escaping |

List Filters

| Filter | Description |

|--------|-------------|

| length | Number of items |

| join:sep | Join items with separator |

| slice:"start:end" | Slice a list/string |

| dictsort:"key" | Sort by key (ascending) |

| dictsortreversed:"key" | Sort by key (descending) |

| sort | Sort items |

| unique | Remove duplicates |

| random | Random item |

| reverse | Reverse order |

| split:sep | Split string into list |

| replace:"old,new" | Replace occurrences |

Default Filters

| Filter | Description |

|--------|-------------|

| default:"fallback" | Show fallback if value is falsy |

| default_if_none:"fallback" | Show fallback if value is null/undefined |

| firstof:v1 v2 v3 | First non-empty value |

Date/Time Filters

| Filter | Description |

|--------|-------------|

| date:"Y-m-d" | Django-style date format |

| time:"H:i" | Django-style time format |

| date_format:"yyyy-MM-dd" | Intl-style date format |

| strftime:"PPPP" | Intl-style time format |

| timesince | Time since date ("2 hours ago") |

| timeuntil | Time until date |

| ago | Short time-ago ("2m", "3h") |

| until | Short time-until |

| time_diff:other_date | Difference between two dates |

Numeric Filters

| Filter | Description |

|--------|-------------|

| add:N | Add N |

| sub:N | Subtract N |

| mult:N | Multiply by N |

| divisibleby:N | Check divisibility |

| mod:N | Modulo |

| floatformat:N | Format float with N decimals |

| square | Square a number |

| sqrt | Square root |

| abs | Absolute value |

| round:N | Round to N decimals |

| floor | Floor |

| ceil | Ceiling |

| min:N | Minimum of value and N |

| max:N | Maximum of value and N |

| sum | Sum of list |

| average | Average of list |

Currency and Data Formatting

| Filter | Description |

|--------|-------------|

| currency:"$" | Format as currency |

| phone_number | Format phone number |

| email | Format as email link |

| url | Format as URL link |

| mask:"*" | Mask sensitive data |

| whatsapp_link:"msg" | Generate WhatsApp link |

| credit_card | Format credit card number |

| ssn | Format SSN |

| ip_address | Format IP address |

| uuid | Format UUID |

| filesizeformat | Human-readable file size |

| yesno:"yes,no,maybe" | Yes/no based on boolean |

| pluralize:"s" | Add plural suffix if needed |

| urlencode | URL-encode |

| escapeuri | Escape URI component |

| stringformat:"%s" | String format |

| cut:"text" | Remove occurrences |

| addslashes | Add slashes |

| removetags:"p,div" | Remove specified tags |

| trans:"key" | Translate key |

| regroup:"attr" | Regroup list by attribute |

| json | Serialize to JSON |

| urlize | Auto-link URLs in text |

Encoding Filters

| Filter | Description |

|--------|-------------|

| base64_encode | Base64 encode |

| base64_decode | Base64 decode |

Next Steps