getFontStyles.js

function getFontStyles(stylesArtboard) {
    // empty "spacers obj" wheree we will store all colors
    const fontStyles = {};
    // get "spacers" artboard
    const fontStylesAtrboard = stylesArtboard.filter(item => {
        return item.name === "typography";
    })[0].children;

    fontStylesAtrboard.map((fontItem, i) => {
        if (fontItem.children) {
            let subFonts = {};

            // get all sub fonts
            fontItem.children.map(subFontItem => {
                let subFontObj = {
                    [subFontItem.name]: {
                        family: {
                            value: `${subFontItem.style.fontFamily}`,
                            type: "typography"
                        },
                        size: {
                            value: `${subFontItem.style.fontSize}px`,
                            type: "typography"
                        },
                        weight: {
                            value: subFontItem.style.fontWeight,
                            type: "typography"
                        },
                        lineheight: {
                            value: `${subFontItem.style.lineHeightPercent}%`,
                            type: "typography"
                        },
                        spacing: {
                            value:
                                subFontItem.style.letterSpacing !== 0
                                    ? `${subFontItem.style.letterSpacing}px`
                                    : "normal",
                            type: "typography"
                        }
                    }
                };
                // merge multiple subfonts objects into one
                Object.assign(subFonts, subFontObj);
            });

            //
            let fontObj = {
                [fontItem.name]: subFonts
            };

            Object.assign(fontStyles, fontObj);
        } else {
            let fontObj = {
                [fontItem.name]: {
                    family: {
                        value: `${fontItem.style.fontFamily}, ${
                            fontItem.style.fontPostScriptName
                        }`,
                        type: "typography"
                    },
                    size: {
                        value: fontItem.style.fontSize,
                        type: "typography"
                    },
                    weight: {
                        value: fontItem.style.fontWeight,
                        type: "typography"
                    },
                    lineheight: {
                        value: `${fontItem.style.lineHeightPercent}%`,
                        type: "typography"
                    },
                    spacing: {
                        value:
                            fontItem.style.letterSpacing !== 0
                                ? `${fontItem.style.letterSpacing}px`
                                : "normal",
                        type: "typography"
                    }
                }
            };

            Object.assign(fontStyles, fontObj);
        }
    });

    return fontStyles;
}