node.js - 比较 Handlebars 的 block 助手

Question

我在代码中使用 block 助手比较值，但每次运行此代码时出现问题，我都会在网页 View 上收到此错误消息

Error: Missing helper: "compare"
    at Object.<anonymous> (/opt/lampp/htdocs/x/chessMult/regtest/using-passport-with-sequelize-and-mysql-master/node_modules/handlebars/dist/cjs/handlebars/helpers/helper-missing.js:19:13)
    at Object.eval (eval at createFunctionContext (/opt/lampp/htdocs/x/chessMult/regtest/using-passport-with-sequelize-and-mysql-master/node_modules/handlebars/dist/cjs/handlebars/compiler/javascript-compiler.js:254:23),
    <anonymous>:8:91)
    at main (/opt/lampp/htdocs/x/chessMult/regtest/using-passport-with-sequelize-and-mysql-master/node_modules/handlebars/dist/cjs/handlebars/runtime.js:175:32)
    at ret (/opt/lampp/htdocs/x/chessMult/regtest/using-passport-with-sequelize-and-mysql-master/node_modules/handlebars/dist/cjs/handlebars/runtime.js:178:12)
    at ret (/opt/lampp/htdocs/x/chessMult/regtest/using-passport-with-sequelize-and-mysql-master/node_modules/handlebars/dist/cjs/handlebars/compiler/compiler.js:525:21)
    at ExpressHandlebars._renderTemplate (/opt/lampp/htdocs/x/chessMult/regtest/using-passport-with-sequelize-and-mysql-master/node_modules/express-handlebars/lib/express-handlebars.js:247:12)
    at ExpressHandlebars.<anonymous> (/opt/lampp/htdocs/x/chessMult/regtest/using-passport-with-sequelize-and-mysql-master/node_modules/express-handlebars/lib/express-handlebars.js:173:21)

我的index.hbs文件

{{#compare pageCount ">" 1 }}
  <ul class="pagination"><­/ul>
    {{#compare  currentPage ">" 1  }}

       <li><a href="/?page=1"> &laquo;</a></li>
    {{/compare}}

{{/compare}}

我的 auth.js 文件

res.render('index', {x:"1888", "personList": personList,data: data, pageSize: pageSize, pageCount: pageCount,currentPage: currentPage});

我的 app.js 文件

const exphbs     = require('express-handlebars');
const hbs = exphbs.create({
  // Specify helpers which are only registered on this instance.
  helpers: {
    foo: function () { return 'FOO!'; },
    extname: ".hbs",
    compare: function(lvalue, rvalue, options) {

      if (arguments.length < 3)
        throw new Error("Handlerbars Helper 'compare' needs 2 parameters");

      var operator = options.hash.operator || "==";

      var operators = {
        '==':       function(l,r) { return l == r; },
        '===':      function(l,r) { return l === r; },
        '!=':       function(l,r) { return l != r; },
        '<':        function(l,r) { return l < r; },
        '>':        function(l,r) { return l > r; },
        '<=':       function(l,r) { return l <= r; },
        '>=':       function(l,r) { return l >= r; },
        'typeof':   function(l,r) { return typeof l == r; }
      }

      if (!operators[operator])
        throw new Error("Handlerbars Helper 'compare' doesn't know the operator "+operator);

      var result = operators[operator](lvalue,rvalue);

      if( result ) {
        return options.fn(this);
      } else {
        return options.inverse(this);
      }

    }

  }
});


//For Handlebars
app.set('views', './app/views')
app.engine('.hbs', exphbs({extname: '.hbs'}));
app.set('view engine', '.hbs');

哪里错了？

Answer 1

app.js 文件中有一个小错误

const exphbs     = require('express-handlebars');
const hbs = exphbs.create({
//...
});

//For Handlebars
app.set('views', './app/views');
app.engine('.hbs', hbs.engine); // <===== Use `hbs.engine`
app.set('view engine', '.hbs');