I would split the logic between appropriate small components to improve readability and get closer to the first SOLID principle - single responsibility.
<!-- begin snippet: js hide: false console: true babel: true -->
<!-- language: lang-js -->
const data = {
'Day 1': {
Chest: {
warmUp: ['parallel bar dips'],
main: ['Bench Press', 'Inclined Bench press', 'Decline Bench press'],
secondary: ['Dumbbell Flys', 'Cable Crossover Flys', 'Pec-deck Fly'],
},
Biceps: {
Lola: ['Barbell Curl', 'Preacher Curl'],
bobo: ['Hammer Curls', 'Cable Curl', 'Dumbbell Curl'],
},
},
}
const ProgramExercises = ({ name, exercises }) => {
return (
<div className="ExerciseType">
<h5>{name}</h5>
<ul>
{exercises.map((name, index) => (
<li key={index}>{name}</li>
))}
</ul>
</div>
)
}
const ProgramPart = ({ name, data }) => {
const types = Object.entries(data)
return (
<div className="Part">
<h2>{name}</h2>
{types.map(([name, exercises], index) => (
<ProgramExercises name={name} exercises={exercises} key={index} />
))}
</div>
)
}
const ProgramDay = ({ name, data }) => {
const parts = Object.entries(data)
return (
<div className="Day">
<h2>{name}</h2>
{parts.map(([name, data], index) => (
<ProgramPart name={name} data={data} key={index} />
))}
</div>
)
}
const Program = ({ program }) => {
const days = Object.entries(program)
return (
<section className="Program">
{days.map(([name, data], index) => (
<ProgramDay name={name} data={data} key={index} />
))}
</section>
)
}
ReactDOM.render(<Program program={data} />, document.getElementById('app'))
console.log(document.getElementById('app').outerHTML)
<!-- language: lang-html -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="app"></div>
<!-- end snippet -->
That's [*property spread notation*][1]. It was added in ES2018 (spread for arrays/iterables was earlier, ES2015), but it's been supported in React projects for a long time via transpilation (as "[JSX spread attributes][2]" even though you could do it elsewhere, too, not just attributes).
`{...this.props}` *spreads out* the "own" enumerable properties in `props` as discrete properties on the `Modal` element you're creating. For instance, if `this.props` contained `a: 1` and `b: 2`, then
<Modal {...this.props} title='Modal heading' animation={false}>
would be the same as
<Modal a={this.props.a} b={this.props.b} title='Modal heading' animation={false}>
But it's dynamic, so whatever "own" properties are in `props` are included.
Since `children` is an "own" property in `props`, spread will include it. So if the component where this appears had child elements, they'll be passed on to `Modal`. Putting child elements between the opening tag and closing tags is just syntactic sugar — the good kind — for putting a `children` property in the opening tag. Example:
<!-- begin snippet: js hide: true console: true babel: true -->
<!-- language: lang-js -->
class Example extends React.Component {
render() {
const { className, children } = this.props;
return (
<div className={className}>
{children}
</div>
);
}
}
ReactDOM.render(
[
<Example className="first">
<span>Child in first</span>
</Example>,
<Example className="second" children={<span>Child in second</span>} />
],
document.getElementById("root")
);
<!-- language: lang-css -->
.first {
color: green;
}
.second {
color: blue;
}
<!-- language: lang-html -->
<div id="root"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<!-- end snippet -->
Spread notation is handy not only for that use case, but for creating a new object with most (or all) of the properties of an existing object — which comes up a lot when you're updating state, since you can't modify state directly:
this.setState(prevState => {
return {foo: {...prevState.foo, a: "updated"}};
});
That replaces `this.state.foo` with a new object with all the same properties as `foo` except the `a` property, which becomes `"updated"`:
<!-- begin snippet: js hide: true console: true babel: false -->
<!-- language: lang-js -->
const obj = {
foo: {
a: 1,
b: 2,
c: 3
}
};
console.log("original", obj.foo);
// Creates a NEW object and assigns it to `obj.foo`
obj.foo = {...obj.foo, a: "updated"};
console.log("updated", obj.foo);
<!-- language: lang-css -->
.as-console-wrapper {
max-height: 100% !important;
}
<!-- end snippet -->
[1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax
[2]: https://reactjs.org/docs/jsx-in-depth.html#spread-attributes
