将自定义车把助手导入到 assemble 的正确方法

Question

有以下 assemble 文件，一切都按预期加载。如果我使用 handlebars-helpers，该文件会编译，但它缺少我需要的助手。所以我不得不使用自定义助手 file/module

var gulp = require('gulp');
var rename = require('gulp-rename');
var assemble = require('assemble');
//var helpers = require('handlebars-helpers');
var app = assemble();
var prettify = require('gulp-prettify');
var config = require('../config');

gulp.task('init', function(cb) {
  app.helpers(config.paths.path_src + 'partials/_helpers/is-helper.js');
  //app.helper('compare', helpers.comparison());
  app.partials(config.paths.path_src + 'templates/includes/**/*.hbs');
  app.layouts(config.paths.path_src + 'templates/layouts/**/*.hbs');
  app.pages(config.paths.path_src + 'templates/content/**/*.hbs');
  cb();
});

gulp.task('assemble', ['init'], function() {
  return app.toStream('pages')
    .pipe(app.renderFile())
    .pipe(prettify({
        indent_inner_html: false,
        preserve_newlines: true,
        end_with_newline: true,
        extra_liners: ['head', 'body']
    }))
    .pipe(rename({
        extname: '.html'
    }))
    .pipe(rename({dirname: ''}))
    .pipe(app.dest('site'));
});

gulp.task('test', ['assemble']);

现在我已经尝试过 handlebars-helper 但它没有我想要的帮助文件所以我不得不使用下面的文件：

/*
    Custom handlebars helpers which allows to make

    {{#is a '===' b}}}

    {{/is}}
*/

module.exports.register = function (handlebars) {

    var isArray = function(value) {
        return Object.prototype.toString.call(value) === '[object Array]';
    }

    var ExpressionRegistry = function() {
        this.expressions = [];
    };

    ExpressionRegistry.prototype.add = function (operator, method) {
        this.expressions[operator] = method;
    };

    ExpressionRegistry.prototype.call = function (operator, left, right) {
        if ( ! this.expressions.hasOwnProperty(operator)) {
            throw new Error('Unknown operator "'+operator+'"');
        }

        return this.expressions[operator](left, right);
    };

    var eR = new ExpressionRegistry;
    eR.add('not', function(left, right) {
        return left != right;
    });
    eR.add('>', function(left, right) {
        return left > right;
    });
    eR.add('<', function(left, right) {
        return left < right;
    });
    eR.add('>=', function(left, right) {
        return left >= right;
    });
    eR.add('<=', function(left, right) {
        return left <= right;
    });

    eR.add('==', function(left, right) {
        return left == right;
    });

    eR.add('===', function(left, right) {
        return left === right;
    });
    eR.add('!==', function(left, right) {
        return left !== right;
    });
    eR.add('in', function(left, right) {
        if ( ! isArray(right)) {
            right = right.split(',');
        }
        return right.indexOf(left) !== -1;
    });

    var isHelper = function() {
        var args = arguments
        ,   left = args[0]
        ,   operator = args[1]
        ,   right = args[2]
        ,   options = args[3]
        ;


        // console.log(args);

        if (args.length == 2) {
            options = args[1];
            if (left) return options.fn(this);
            return options.inverse(this);
        }

        if (args.length == 3) {
            right = args[1];
            options = args[2];
            if (left == right) return options.fn(this);
            return options.inverse(this);
        }

        if (eR.call(operator, left, right)) {
            return options.fn(this);
        }
        return options.inverse(this);
    };

    handlebars.registerHelper('is', isHelper);

    return eR;
};

我不断收到以下错误，缺少助手 "is"。好像没有注册！ 请帮忙！！！

Answer 1

参照this github issue:

is 帮助文档是 here。

Also is there a way to import custom helpers?

这是描述here。您不使用路径，而是使用 require:

// single helper (required module returns the helper function)
app.helper('is', require('./helpers/is'));

// multiple helpers (required module returns an object of helper functions... e.g. key/value pairs)
app.helpers(require('./helpers'));

上面的自定义助手代码使用 grunt-assemble 语法来注册助手。在这种情况下，我会将您的助手更改为如下所示：

/*
    Custom handlebars helpers which allows to make

    {{#is a '===' b}}}

    {{/is}}
*/

module.exports = function () {

    var isArray = function(value) {
        return Object.prototype.toString.call(value) === '[object Array]';
    }

    var ExpressionRegistry = function() {
        this.expressions = [];
    };

    ExpressionRegistry.prototype.add = function (operator, method) {
        this.expressions[operator] = method;
    };

    ExpressionRegistry.prototype.call = function (operator, left, right) {
        if ( ! this.expressions.hasOwnProperty(operator)) {
            throw new Error('Unknown operator "'+operator+'"');
        }

        return this.expressions[operator](left, right);
    };

    var eR = new ExpressionRegistry;
    eR.add('not', function(left, right) {
        return left != right;
    });
    eR.add('>', function(left, right) {
        return left > right;
    });
    eR.add('<', function(left, right) {
        return left < right;
    });
    eR.add('>=', function(left, right) {
        return left >= right;
    });
    eR.add('<=', function(left, right) {
        return left <= right;
    });

    eR.add('==', function(left, right) {
        return left == right;
    });

    eR.add('===', function(left, right) {
        return left === right;
    });
    eR.add('!==', function(left, right) {
        return left !== right;
    });
    eR.add('in', function(left, right) {
        if ( ! isArray(right)) {
            right = right.split(',');
        }
        return right.indexOf(left) !== -1;
    });

    var isHelper = function() {
        var args = arguments
        ,   left = args[0]
        ,   operator = args[1]
        ,   right = args[2]
        ,   options = args[3]
        ;


        // console.log(args);

        if (args.length == 2) {
            options = args[1];
            if (left) return options.fn(this);
            return options.inverse(this);
        }

        if (args.length == 3) {
            right = args[1];
            options = args[2];
            if (left == right) return options.fn(this);
            return options.inverse(this);
        }

        if (eR.call(operator, left, right)) {
            return options.fn(this);
        }
        return options.inverse(this);
    };

    return isHelper;
};

在 assemble 中，您可以通过以下方式加载助手：

var isHelper = require(config.paths.path_src + 'partials/_helpers/is-helper'));
app.helper('is', isHelper());

请注意，从 is-helper 返回的函数在传递给 app.helper 之前被调用。这允许您将自定义选项传递给您的助手（例如，您在助手中使用的自定义表达式），但这取决于您。

希望对您有所帮助。

将自定义车把助手导入到 assemble 的正确方法

Correct way to import custom handlebar helpers to assemble

handlebars.js

assemble