Render array of inputs in react

- 1 answer

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I have an array of emails (as a part of a bigger model). These are displayed in seperate rows witha remove button for each (the address itself can be updated in the input box directly). Unfortunately I dont know how to do this in react when the inputs are renderd using a map function. (I am converting a meteor blaze project to meteor react).

Everything renders but how do I attach to change event so I can update my array of emails? onChange + value need to be set somehow.

This is the map function

return this.data.emailGroup.emails.map((email) => {
            return (
                <div key={email} className="input-group">
                    <input type="text" className="form-control" onChange={self.handleEmailListChange} value={email}/>

                    <div className="input-group-btn">
                        <button type="button"
                                className="btn btn-default remove-email"><span
                            className="glyphicon glyphicon-remove"></span></button>
                    </div>
                </div>
            );
        });

The initial state(which is populated with data from the db:

 getInitialState() {
      return {
          name : '',
          description: '',
          emails : [],
          newEmailAddress : ''
      }
    },

Upon request here is the render method(it requires a getContent method.The getcontent method is there because in meteor I need to wait for data so in the meantime I need a loading state.

   getContent() {
        return (

            <div className="box box-success">
                <div className="box-header with-border">
                    <h3 className="box-title">List of emails</h3>
                </div>
                <form role="form" className="form-horizontal">
                    <div className="box-body">
                        <p>Below is a list of email addresses which are added to this email group. If
                            you
                            want
                            to add more
                            you can add them one by one by inputting in the box below or add a list into
                            the
                            same box (email
                            addresses have to be seperated by either a space or ;) then press Add to add
                            to
                            the
                            list. You can edit
                            the addresses directly as well as remove them.</p>
                        <div className="input-group">
                            <input type="text" className="form-control"

                                   value={this.state.newEmailAddress}
                                   onChange={this.handleAddNewEmail}
                                   placeholder="Email addresses seperated by a space or a semicolon ; i.e. [email protected];[email protected]"/>
                    <span className="input-group-btn">
                      <button type="button" onClick={this.handleAddNewEmailButton} className="btn btn-info btn-flat add-email">Add</button>
                    </span>
                        </div>
                        <br/>
                        {this.renderEmail()}
                    </div>
                </form>
            </div>
        )
    },
    render()
    {
    var contentStyle = {
        minHeight : '946px'
    };
        return (
            <div className="content-wrapper" style={contentStyle}>
                <section className="content-header">
                    <h1>
                        {this.data.emailGroup? this.data.emailGroup.name : 'hello'}
                    </h1>
                    <small> Created by: Christian Klinton</small>
                    <br/>
                    <small> Last updated by: Christian Klinton - 2015-11-12 08:10:11</small>
                    <ol className="breadcrumb">
                        <li><a target="_blank" rel="nofollow noreferrer" target="_blank" rel="nofollow noreferrer" href="/emailGroups"><i className="fa fa-dashboard"></i> Home</a></li>
                        <li><a target="_blank" rel="nofollow noreferrer" target="_blank" rel="nofollow noreferrer" href="/emailGroups">Email groups</a></li>
                        <li className="active">{this.data.emailGroup? this.data.emailGroup.name : 'loading'}</li>
                    </ol>
                </section>
                <section className="content">
                    <div className="row">
                        <div className="col-md-6">
                            <div className="box box-primary">
                                <div className="box-header with-border">
                                    <h3 className="box-title">Information</h3>

                                </div>
                                <form role="form">
                                    <div className="box-body">
                                        <div className="form-group">
                                            <label htmlFor="inputName">Name</label>
                                            <input type="email" className="form-control" id="name"
                                                   onChange={this.handleNameChange}
                                                   placeholder="Set the name of the email group" autoComplete="off"
                                                  value={this.state.name}/>
                                        </div>

                                        <div className="form-group">
                                            <label>Description</label>
                                    <textarea className="form-control" rows="3" id="description"
                                              placeholder="Enter a description what and how the template is used..."
                                              onChange={this.handleDesriptionChange}
                                              value={this.state.description}
                                    ></textarea>
                                        </div>


                                    </div>
                                </form>
                            </div>
                        </div>
                        <div className="col-md-6">
                            {this.data.emailGroup? this.getContent() : <p>Loading</p> }
                        </div>
                        <div className="form-group">
                            <div className="col-sm-offset-8 col-sm-4">
                                <div className="pull-right">
                                    <button className="btn btn-primary">Delete all</button>
                                    <button className="btn btn-primary save">Save</button>
                                </div>
                            </div>
                        </div>
                    </div>
                </section>
            </div>
        )
    }
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Answer

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React requires you to have something unique for every element in the rendered array, it's called a key, and it's an attribute.

If you don't know what to assign to the key, just assign it the array's indexes:

this.props.doors.map((door, index) => (
    <div key={index} className="door"></div>
));

Here's the same solution applied to your problem:

return this.data.emailGroup.emails.map((email, index) => {
    return (
        <div key={index} className="input-group">
            <input type="text"
                   className="form-control"
                   onChange={self.handleEmailListChange.bind(this, index)} value={email}/>
        </div>
    );
});

Notice how I bound handleEmailListChange to receive the index of the modified email. If handleEmailListChange accepts an index, it can update the modified email within the state:

handleEmailListChange: function(index, event) {
    var emails = this.state.emails.slice(); // Make a copy of the emails first.
    emails[index] = event.target.value; // Update it with the modified email.
    this.setState({emails: emails}); // Update the state.
}
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source: stackoverflow.com
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