Files
handlebars.js/lib/handlebars/helpers/if.js
T
Hannah Wolfe c76ded8f0f fix: add guard to if & unless helpers (#1549)
fixes #1548

- add a guard to show readable syntax error for if / unless helper
- prevents against 3 different errors that can be generated by different systax errors
2019-10-27 15:41:35 +01:00

24 lines
1.1 KiB
JavaScript

import { isEmpty, isFunction } from '../utils';
import Exception from '../exception';
export default function(instance) {
instance.registerHelper('if', function(conditional, options) {
if (arguments.length != 2) { throw new Exception('#if requires exactly one argument');}
if (isFunction(conditional)) { conditional = conditional.call(this); }
// Default behavior is to render the positive path if the value is truthy and not empty.
// The `includeZero` option may be set to treat the condtional as purely not empty based on the
// behavior of isEmpty. Effectively this determines if 0 is handled by the positive path or negative.
if ((!options.hash.includeZero && !conditional) || isEmpty(conditional)) {
return options.inverse(this);
} else {
return options.fn(this);
}
});
instance.registerHelper('unless', function(conditional, options) {
if (arguments.length != 2) { throw new Exception('#unless requires exactly one argument');}
return instance.helpers['if'].call(this, conditional, {fn: options.inverse, inverse: options.fn, hash: options.hash});
});
}