lsm9ds1

Thanks @luwar.
I did some trials using the following module code located in my local projects/modules directory

/***************************************­***************************************
Starting to recode this for Espruino 11/30/2016
LSM9DS1_Registers.h
SFE_LSM9DS1 Library - LSM9DS1 Register Map
Jim Lindblom @ SparkFun Electronics
Original Creation Date: April 21, 2015
https://github.com/sparkfun/LSM9DS1_Brea­kout

This file defines all registers internal to the gyro/accel and magnetometer
devices in the LSM9DS1.

Development environment specifics:
	IDE: Arduino 1.6.0
	Hardware Platform: Arduino Uno
	LSM9DS1 Breakout Version: 1.0

This code is beerware; if you see me (or any other SparkFun employee) at the
local, and you've found our code helpful, please buy us a round!

Distributed as-is; no warranty is given.
****************************************­**************************************/

////////////////////////////////////////­/
// LSM9DS1 Accel/Gyro (XL/G) Registers //
////////////////////////////////////////­/
var Regs={
 ACT_THS:0x04,
 ACT_DUR:0x05,
  INT_GEN_CFG_XL:	(0x06),
  INT_GEN_THS_X_XL:	(0x07),
  INT_GEN_THS_Y_XL:	(0x08),
  INT_GEN_THS_Z_XL:	(0x09),
  INT_GEN_DUR_XL:	(0x0A),
  REFERENCE_G:		(0x0B),
  INT1_CTRL:		(0x0C),
  INT2_CTRL:		(0x0D),
  WHO_AM_I_XG:		(0x0F),
  CTRL_REG1_G:		(0x10),
  CTRL_REG2_G:		(0x11),
  CTRL_REG3_G:		(0x12),
  ORIENT_CFG_G:		(0x13),
  INT_GEN_SRC_G:	(0x14),
  OUT_TEMP_L:		(0x15),
  OUT_TEMP_H:		(0x16),
  STATUS_REG_0:		(0x17),
  OUT_X_L_G:		(0x18),
  OUT_X_H_G:		(0x19),
  OUT_Y_L_G:		(0x1A),
  OUT_Y_H_G:		(0x1B),
  OUT_Z_L_G:		(0x1C),
  OUT_Z_H_G:		(0x1D),
  CTRL_REG4:		(0x1E),
  CTRL_REG5_XL:		(0x1F),
  CTRL_REG6_XL:		(0x20),
  CTRL_REG7_XL:		(0x21),
  CTRL_REG8:		(0x22),
  CTRL_REG9:		(0x23),
  CTRL_REG10:		(0x24),
  INT_GEN_SRC_XL:	(0x26),
  STATUS_REG_1:		(0x27),
  OUT_X_L_XL:		(0x28),
  OUT_X_H_XL:		(0x29),
  OUT_Y_L_XL:		(0x2A),
  OUT_Y_H_XL:		(0x2B),
  OUT_Z_L_XL:		(0x2C),
  OUT_Z_H_XL:		(0x2D),
  FIFO_CTRL:		(0x2E),
  FIFO_SRC: 		(0x2F),
  INT_GEN_CFG_G:	(0x30),
  INT_GEN_THS_XH_G:	(0x31),
  INT_GEN_THS_XL_G:	(0x32),
  INT_GEN_THS_YH_G:	(0x33),
  INT_GEN_THS_YL_G:	(0x34),
  INT_GEN_THS_ZH_G:	(0x35),
  INT_GEN_THS_ZL_G:	(0x36),
  INT_GEN_DUR_G:	(0x37)
};

///////////////////////////////
// LSM9DS1 Magneto Registers //
///////////////////////////////
var Mags={
  OFFSET_X_REG_L_M:	0x05,
  OFFSET_X_REG_H_M:	0x06,
  OFFSET_Y_REG_L_M:	0x07,
  OFFSET_Y_REG_H_M:	0x08,
  OFFSET_Z_REG_L_M:	0x09,
  OFFSET_Z_REG_H_M:	0x0A,
  WHO_AM_I_M:			0x0F,
  CTRL_REG1_M:			0x20,
  CTRL_REG2_M:			0x21,
  CTRL_REG3_M:			0x22,
  CTRL_REG4_M:			0x23,
  CTRL_REG5_M:			0x24,
  STATUS_REG_M:		0x27,
  OUT_X_L_M:			0x28,
  OUT_X_H_M:			0x29,
  OUT_Y_L_M:			0x2A,
  OUT_Y_H_M:			0x2B,
  OUT_Z_L_M:			0x2C,
  OUT_Z_H_M:			0x2D,
  INT_CFG_M:			0x30,
  INT_SRC_M:			0x30,
  INT_THS_L_M:			0x32,
  INT_THS_H_M:		0x33
};

////////////////////////////////
// LSM9DS1 WHO_AM_I Responses //
////////////////////////////////
var WHO_AM_I_AG_RSP=0x68;
var WHO_AM_I_M_RSP=0x3D;


////////////////////////////////////////­/////
function LSM9DS1(i2c) {
  this.i2c = i2c;
  this.addr = 0x48;
  this.gain = 2048;
}
// Create an instance of LSM9DS1
exports.connect = function(i2c1) {
  return new LSM9DS1(i2c1);
};

I invoke this experimental module using the following:

/* 
Test Module for the LSM9DS1
*/
console.log(process.memory());
I2C1.setup({ scl :B6, sda: B9} );
var W=require("LSM9DS1").connect(I2C1);
console.log(process.memory());

The output with No Module minification

>{ "free": 4565, "usage": 535, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }
{ "free": 4535, "usage": 565, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }

Module minification Esprima (offline)

>{ "free": 4765, "usage": 335, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }
{ "free": 4735, "usage": 365, "total": 5100, "history": 0,

Module minification Closure (online) –Whitespace only

>{ "free": 4762, "usage": 338, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }
{ "free": 4732, "usage": 368, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }

Module minification Closure (online) – Simple optimizations

>{ "free": 4765, "usage": 335, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }
{ "free": 4735, "usage": 365, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }

Module minification Closure (online) – Advanced

>{ "free": 5027, "usage": 73, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }
{ "free": 4999, "usage": 101, "total": 5100, "history": 0,
  "stackEndAddress": 536959408, "flash_start": 134217728, "flash_binary_end": 379112, "flash_code_start": 134234112, "flash_length": 393216 }

From the Usage values the Advanced option seems to do the best job..