const regex = new RegExp('([\\w_\\.]+)=([\\-\\w_\\.]+);', 'gm')
const str = `g_MA1=17;
g_MA2=20;
ExtTimeWindowStart=7;
ExtTimeWindowDuration=14;
ExtDayNotToTrade=6;
g_FilterState=0;
g_MAType=3;
g_use_MA_Factor=0;
g_MA_LB_Factor=2;
g_activateMA3=0;
g_MA3=80;
g_activateBBKC=0;
g_BBKCHighVolatility=0;
g_BBKC=10;
g_BBKCThreshold=0.75;
g_BBKCBarsLength=1;
g_activateSNR=1;
g_SNRCycle=0;
g_SNRPeriod=25;
g_SNRLevel=-15;
g_SNRBarsLength=1;
g_activateTI=1;
g_TI_LB=20;
g_MA1_Weight=3;
g_MA2_Weight=2;
g_MA3_Weight=1;
g_MA_TypeTI=3;
g_IsNormalized=1;
g_UpperThreshold=30;
g_LowerThreshold=-30;
g_orderType=0;
g_inversionSwitch=1;
g_barsNumber=3;
g_averageFactor=0;
g_DayLength=1;
g_activateOpposite=1;
g_activateDayTrade=0;
g_activateTradeDuration=0;
g_tradeDurationBars=10;
ExtSlPercent=0.25;`;
const subst = `\1=\2\n\1,F=0\n\1,1=0\n\1,2=0\n\1,3=0`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions