MentorAPM Jr. Dev Interview Cheat Sheet

loop.js

(async function () {

	const { layers } = await (await fetch('https://.../arcgis/rest/services/.../MapServer?f=pjson')).json();

	const layersById = layers.reduce((acc, item) => {
		acc[item.id] = item;
		return acc;
	}, {});

	let usedIcons = [];
	const icon = () => {
		const generateRandomIcon = () => {
			const rn = Math.floor(Math.random() * (Math.floor(9983) - Math.ceil(9728) + 1)) + Math.ceil(9728);
			return String.fromCharCode(rn);
		};
		let newIcon = generateRandomIcon();
		while (usedIcons.includes(newIcon)) {
			newIcon = generateRandomIcon();
		}
		usedIcons.push(newIcon);
		return newIcon;
	};

	const recurseLayer = (layerId, recursionLevel) => {
		let layer = layersById[layerId];
		console.log('\t'.repeat(recursionLevel) + icon() + ' ' + layer.name);
		for (let i=0, l=(layer.subLayerIds || []).length; i<l; i++) {
			const subLayerId = layer.subLayerIds[i];
			recurseLayer(subLayerId, (recursionLevel+1));
		}
	};

	for (let id in layersById) {
		let layer = layersById[id];
		if (layer.parentLayerId === -1) {
			recurseLayer(id, 0);
		}
	}

}());