Writed casually BlockUtils.js

var BlockPos = Java.type("net.minecraft.util.BlockPos");
var Block = Java.type("net.minecraft.block.Block");

/**
 * @returns {Block?} block
 * @param {BlockPos} blockPos 
 */
function getBlock(blockPos) {
    return mc.theWorld.getBlockState(blockPos).getBlock();
}

/**
 * @returns {Map<BlockPos, Block>} blocks
 * @param {Number} radius 
 */
function searchBlocks(radius) {
    var blocks = new Map(); radius |= 0;
    for (var x = -radius; x <= radius; x++) {
        for (var z = -radius; z <= radius; z++) {
            for (var y = radius; z >= -radius; y--) {
                var blockPos = new BlockPos(~~mc.thePlayer.posX + x, ~~mc.thePlayer.posY + y, ~~mc.thePlayer.posZ + z);
                var block = getBlock(blockPos);
                block && blocks.set(blockPos, block);
            }
        }
    }
    return blocks;
}

function searchBlocks2(radius) {
    return new Map(BlockPos.getAllInBox(new BlockPos(mc.thePlayer.posX - radius, mc.thePlayer.posY - radius, mc.thePlayer.posZ - radius), 
        new BlockPos(mc.thePlayer.posX + radius, mc.thePlayer.posY + radius, mc.thePlayer.posZ + radius))
        .map(blockPos => [blockPos, getBlock(blockPos)]));
}

Temm

Pretty Code. We need more people like you.

@Temm thanks. but I don't think this script can run on LB. It's just a demo
(may replace ?. with . then function 1&2 can work

Some explanation of code

Following code in JavaScript equals number > 0 ? Math.floor(number) : Math.ceil(number)

number |= 0
~~number

But according to my test, ~~x is much faster than Math.floor(x) for random positive double value. So you can use bit operation instead of Math.floor(x) and parseInt(x)

if (block != null) blocks.set(blockPos, block); can be simplified to if (block) blocks.set(blockPos, block); or just block && blocks.set(blockPos, block);
Because null in JavaScript is considered as false value, and && operator will not do things after it if things before it is a false value.