JavaScript function to categorize data by their "styles" attribute, and store the key-"unicode" pair

Question

I have a JavaScript function to categorize data by their "styles" attribute, and store the key-"unicode" pair.

Here's my current code:

function processMetadata(metadata) {
    let regular = {}, solid = {}, brands = {}
    for (let icon in metadata) {
        let styles = metadata[icon].styles
        let codePoint = metadata[icon].unicode
        if (styles.includes('regular')) {
            regular[icon] = codePoint
        }
        if (styles.includes('solid')) {
            solid[icon] = codePoint
        }
        if (styles.includes('brands')) {
            brands[icon] = codePoint
        }
    }
    return {regular, solid, brands}
}

However, CodeClimate keeps complaining about

Function processMetadata has a Cognitive Complexity of 7 (exceeds 5 allowed). Consider refactoring.

I want to resolve this issue, but I'm not aware of any way to further reduce the complexity without reducing the performance of this code. The following snippet does reduce the cognitive complexity to under 5 but at the expense of performance (3+3 loops instead of 1) and extra dependency:

function processMetadata(metadata) {
    let regular = _.pickBy(metadata, icon => icon.styles.includes('regular'))
    regular = _.mapValues(regular, icon => icon.unicode)
    let solid = _.pickBy(metadata, icon => icon.styles.includes('solid'))
    solid = _.mapValues(solid, icon => icon.unicode)
    let brands = _.pickBy(metadata, icon => icon.styles.includes('brands'))
    brands = _.mapValues(brands, icon => icon.unicode)
    return {regular, solid, brands}
}

Is there any way I can achieve this without having a significant impact on the performance?

Answer 1

First off, some code review items;

• Don't skip on semicolons
• You are not changing a number of variables, consider const over let in those cases
• The names of your styles match the names of your variables, you could use this

Given that, I would consider something like this

function processMetadata(metadata) {
    let out = {regular: {}, solid: {}, brands: {}};
    for (const icon in metadata) {
        const styles = metadata[icon].styles;
        const codePoint = metadata[icon].unicode;
        for(const style in out){
            if (styles.includes(style)) {
                out[style][icon] = codePoint;
            }
        }
    }
    return out;
}