React - 如何将值传递给组件中的过滤功能？

Question

I am trying to build a simple to-do app.

I store all my tasks in an array like this:

var TASKS = [
  {
    name: "Pay Bills",
    completed: false,
    id: 1,
  },
  {
    name: "Go shopping",
    completed: false,
    id: 2,
  },
  {
    name: "Pick up something",
    completed: false,
    id: 3,
  },
  {
    name: "Drink Coffee",
    completed: true,
    id: 4,
  },
];

and I want to list them in separated sections (todo/done) by passing boolean value as props to the listing component.

My component structure is here:

var Application = React.createClass({
  propTypes: {
    title: React.PropTypes.string,
  },

  getDefaultProps: function() {
    return {
      title: "Add item",
    }
  },

  onTodoAdd: function(name) {
      ...
  },

  onRemoveTask: function(index) {
      ...
  },

  onCompletedTask: function(index) {
      ...
  },

  render: function() {
    return (
      <div className="to-do">

        <Section title={this.props.title}>
          <AddTodoForm onAdd={this.onTodoAdd} />
        </Section>

        <Section title="to-do">
          <ListTasks initialTasks={TASKS} completedTasks={false} />
        </Section>

        <Section title="done">
          <ListTasks initialTasks={TASKS} completedTasks={true} />
        </Section>
      </div>
    );
  }
});

and the listing component looks like this:

var ListTasks = React.createClass({
  propTypes: {
    initialTasks: React.PropTypes.array.isRequired,
    completedTasks: React.PropTypes.bool.isRequired,
  },

  getInitialState: function() {
    return {
      tasks: this.props.initialTasks,
    };
  },

  render: function() {
    return (
      <div>
        {this.state.tasks
        .filter(function(task, index, props) {
          return task.completed === props.completedTasks;
        })
        .map(function(task, index) {
          return(
            <Task
              name={task.name}
              key={task.id}
              completed={task.completed}
              onCompleted={function() {this.onCompletedTask(index)}.bind(this)}
              onRemove={function() {this.onRemoveTask(index)}.bind(this)}
            />
          );
        }.bind(this))}
      </div>
    );
  }
});

but I canť pass the

completedTasks={true/false}

to the filter function with

props.completedTasks

is there anyone who can help please?

Thanks a lot.

Answer 1

The issues is within ListTasks component in render method.

The 3rd parameter of the Array.filter method is not the component props , is an array ( The array filter was called upon).

To fix this you can define a new variable (props) and you can access it within your inner function through lexical scoping

 render: function() {
    var props = this.props;
    return (
      <div>
        {this.state.tasks
        .filter(function(task, index) {
          return task.completed === props.completedTasks;
        })
        .map(function(task, index) {
          return(
            <Task
              name={task.name}
              key={task.id}
              completed={task.completed}
              onCompleted={function() {this.onCompletedTask(index)}.bind(this)}
              onRemove={function() {this.onRemoveTask(index)}.bind(this)}
            />
          );
        }.bind(this))}
      </div>
    );
  }